My 67 442 Oil Pressure and Temperature Hot Warning Lights are not illuminating at all when start the engine or in the accessory position. Quite frankly I don't know if they ever worked since I bought the car - I am just now checking it. The Generator Light is working properly. The easiest thing I would suspect to do is to check the fuse. When I go to the service manual there is a picture of the fuse box on the left. however, in the picture there is nothing mentioned about Warning Lights. That is the fuse box under the dash by where you left foot would be driving. On the right picture, there is a diagram that shows the Oil and Temp Warning Lights, but I don't know what that diagram is. Does anyone know what that is and where it is located? Is there a fuse for the warning lights?

I thought I would ask this first because before replacing the bulbs. Do I need to remove the dash to replace the bulbs?

Please help as I just realized it is very dangerous to be driving the car without these warning lights.

 

I am still curious as to what that diagram is, but in any event when looking at the service manual again, it is not crystal clear but it appears that One single fuse provides electricity all 3 warning lights (GEN, TEMP, OIL), therefore, if my GEN light works, my hunch is that it is not a bad fuse, but either my TEMP and OIL bulbs are bad or something is wrong with those two circuits.

 

By the way, just as a double check, for all you 67 Cutlass/442 owners, does your Oil and Temp Warning Lights illuminate when you turn the key clockwise (but before starting the car)?

 

Look at the fuse cavity labeled INST BU. You see the legend beside it says BACKUP LAMPS, PARKING BRAKE (warning lamp) and INSTRUMENT PANEL FEED. This is the fuse for the dash warning lights.

EZ fuse check is see if the backup lamps work. If not, fuse is probably burnt out.

If backup lamps work, turn ignition switch to RUN and then ground the temp (green) and oil (blue) sender wires to the engine block or other suitable ground. If the lights still don't light, check dashboard bulbs.

Past that, check the green wire on the ignition switch. That's an internal ground that allows the bulb test feature to work when switch is in RUN.

I sure hope your⚡problem is simpler than that Toronado we've been fighting with all week.🤪🤯

 

Thank you Rocket. Well some good news, I went underneath the dash and lo and behold, I have no Oil and Temp Warning Light Bulbs!!! Who would take those out and not replace?

The Good news is, I took a dash light bulb and inserted it into the Oil Warning Light and turned the Ignition and that illuminated. However, when I inserted the bulb into the Temp Sensor socket, the Temp Sensor socket did not illuminate. So either that old bulb does not work in the Temp sensor socket or something is not cooperating with the wiring.

Underneath the dash, in the same harness with wires to the ignition, there is an orange wire that has a plug that is not connected - don't know what that is for , but probably unrelated.

Looking at the engine block there are two sensors on the block. On the drivers side, it is an orange wire. On the passenger side, there is a green wire. I should turn the key and ground those two to troubleshoot the temp sensor?

 

Also to clarify that not only was I missing the Oil and Temp bulbs, but the socket as well so I have to order more bulbs and sockets.

But so far when I put a working bulb and socket in the Temp sensor location, it did not illuminate

 

The green wire on passenger side of the engine goes to the temperature light sending unit. I have no idea what that orange wire on driver side would go to unless someone did some wiring repair on the blue oil sender wire and used whatever color wire was handy. Look close for that blue wire if it means unwrapping some of the wire harness tape.

I'm looking at the 66 CSM V8 wiring diagram and the only orange wire it shows underhood goes to the transmission downshift/switch pitch switch on the carb linkage. A stickshift car would still have the wire, just not connected. 67 would be similar.

Try grounding the green wire with ignition switch in RUN and see if the temp warning lights. If it doesn't with a known good bulb, there's an open somewhere in the circuit. Could be the printed circuit, could be the bulkhead, could be a broken wire.

As far as who does that, taking the warning lamps out? No electrical weirdness I see on any muscle car, no matter the brand, surprises me anymore. You usually don't see it as much on Olds or Buick, but I've seen some scary **** on Chevys and Pontiacs. We won't even talk about Ford and Chrysler.

 

Thank you Rocket! Good news followed what you said and think I need a new temp sensor.

I double checked the wiring and the green wire goes to DRIVER side behind the water pump ( I believe that is the oil pressure sensor).

On the PASSENGER side on the manifold is the orange wire (I believe that is the temp sensor). Appears that is not the original color wiring? In any event, I grounded the manifold sensor and the TEMP light illuminated. So I ordered a temp sensor. Mine is the type that has a little singular disk on top, not a two-prong type. Any recommendations on what to spray on the sensor as it looks corroded at the block. Was surprised because the one on Rock Auto is a two prong, but appears there are two types for this car?

For kicks and giggles I also put a ammeter at the temp sensor and think it was like 10 ohms. In any event I ordered a new temp sensor! So glad that the TEMP light went on! Hopefully a new sensor does the trick - appreciate it! I forget about this idea.

 

Your dash has warning lights so you need the sender unit with prongs. The one on the engine with the flat button top is for Rocket Rallye-Pac gages. The Rallye-Pac wiring is a bit different than warning lamps too.

The F85/Cutlass use a single prong temperature light sender. Big cars used a two-prong sender as they had both a COLD and HOT warning light. You can use the two prong, just have to make sure to get the right wire on the right prong.

What a gage sender will do with a warning light is: the lamp won't test with ignition switch, and the warning lamp will glow brighter as coolant warms up.

My 67 CSM is packed up so I can't get the Rallye-Pac wiring configuration right now to see if the wiring colors are different. Hopefully someone has theirs handy!

(I dug out the 66 for the Toronado's wiring disaster. I keep on I'll have the whole 1950-87 CSM library unpacked!)

 

To get the sender out: spray PB Blaster, Liquid Wrench, Kroil or other penetrating oil on the threads a couple times a day while you wait for the new sending unit. WD40 is not suitable for this.

Then- 6 point socket and a breaker bar, 1/2" drive if you have it. If you have an impact wrench you can use that.

 

Thank you I just sprayed.

By the way, I clarified in my prior post what was on Passenger and Driver side (I had it back wards).

To recap, I have warning lights and my temp sensor is of the round flat top type perpendicular to threads (it is not a singular rectangular type parallel to the threads) . I guess it does not matter which sending one uses as long as the socket fits, correct? I cannot imagine the set point for the sensor being different.

I hope I don't have to buy the rectangular type and buy a new socket. I already ordered the round top replacement, but will order this type too if have to.

By the way, don't have have COLD indicator on my warning light cluster so I am assuming I should not buy the two prong.

 

By the way just FYI, this one Ebay (rectangular single prong) says it is for the Rally Pac.
rally pack temp gauge sender sending unit 68 69 66 67 70 71 temperature sensor | eBay


This is the type that I have:
New Genuine AC Delco Temperature Sender G1852 12334869 Fits various GM 1953-1981 | eBay

 

Rocket; and any other OC members.......Now next step is finding out the oil pressure issue ……at idle it’s sits good at but as it heats up drops low …..when I hit the throttle to come off the fresh start idle then it really gets low …..

Ive been told that my timing seems off ……

What I’ve done so far: fresh oil change with thicker weight oil ….added a half a bottle of Lucas oil treatment (see pic)

Jacked up engine dropped oil pan expected the oil pan for debris and shavings ( all was clear)

Inspected the oil pump ( Melling M22Fsee pic) nothing clogging screen also this pump was put in years ago however very little miles has put on been sitting mostly.

 

Now next step is finding out the oil pressure issue ……at idle it’s sits good at but as it heats up drops low …..when I hit the throttle to come off the fresh start idle then it really gets low …..

Ive been told that my timing seems off ……

What I’ve done so far: fresh oil change with thicker weight oil ….added a half a bottle of Lucas oil treatment (see pic)

Jacked up engine dropped oil pan expected the oil pan for debris and shavings ( all was clear)

Inspected the oil pump ( Melling M22Fsee pic) nothing clogging screen also this pump was put in years ago however very little miles has put on been sitting mostly.

 

OC members pics are to show a visual of how the bottom end looks as well the oil pump.......my thinking and info I've gathered that my timing may have a important factor in idling and oil pump pressure.

So I will look to see if my timing is out but in the interim if anyone has any thoughts on oil pressure ......let me know

 

Something's wacky here. Last 3 posts are word for word duplicates of posts boamridge made in his other threads.

Be there spooks 🧟‍♂️ in the software? A ghost 👻 in the machine?

Matchek, seems awhile back someone on here posted that some gage temperature senders had the prong. But since you have warning lights and not gages, get the warning light sending unit. They are different.

 

These are ignition fired lights, they won't light in accessory. There is no temp test light feed, the temp will only light up when it is hot. There is also no oil test feed, the oil light will only light up with no oil pressure. You should see an oil light come on with ignition before cranking, that and GEN for battery. I'll double check the wiring diagrams.

It's not a big deal to drive the car without these. You will hear a ton of clunking if you lose oil, and boil over when hot. Both of these are noticeable events. If you keep your head in the game, you should notice spiking temp and plunging oil pressure as the lights do. I mean, get it working, but it's not an OMG I'M GONNA DIE thing, you can drive the car.

 

Hey Boamridge, would love to read your posts, but they accidentally were posted on this thread.

Thank you Rocket - would you happen to know which temp sensor is for warning lights? I cannot find it written anywhere. I currently have the one that has round circular top. When I shop for the sensors online , I get different model numbers at the different sites.

Koda - Thank you for posting, but I don't think you are right on the operation of the Warning Lights. According to the Owners and Service Manual, it says that they the Warning lights illuminate before starting and the wiring diagram supports it. - this is to check that they work, which in fact did work for me. This why I knew I had a problem. My GENERATOR and OIL Warning Light are doing that now and working properly, but not the TEMP LIGHT. I believe I have a faulty Temp sensor - will see after a new one is installed. This is how my 68 Olds operates as well .

By the way, I also disagree with how important the Warning Light are - at least for me - I have the music on loud. lol And also with the headers the exhaust rumbles. I am alert but I would certainly would prefer to have the Warning Lights working in normal operation although I would chance it for a short ride. I want to enjoy classic rock and not have to be so focused on the engine at every moment.

 

By the way, I don't think this matters for this thread, but my engine is a 425 engine, not a 400.

 

Matchek/ Koda I think these post were my error.....so apologies to posting on your thread........Rocket Raider has been helping me with disecting my 69 olds 350rocket oil pressure issues.......

So along with Rocket helping me feel free to help as well as direct my post to the appropriate thread

Thanks All

 

Wayal... I had wondered if there'd been an engine swap, because of the conflicting wire colors... But true, the sending units and wiring are the same 330/400/425.

 

I read the temp one wrong, you are correct, there is a wire that there does that. You may also wish to check the wire to the sender. My lights aren't important because the car is in bad shape. If you are going to cruise, that makes sense. Don't feel like you can't short drive it, however, if those parts run late.

 

As an update, I installed a new temp sensor and the HOT light does not illuminate with the car in the first start position without car running. However the HOT light does illuminate when I ground the sensor. My hunch is that when they installed the 425 engine, they did not wire it correctly unless both the old and new sensors are bad.

In addition, what is weird, is I put a new OIL light bulb (before it was missing) and now the OIL light stays on when the car is in the first start position and when it is running. The only was to shut off the oil light is to turn the car off. I am befuddled. How do I diagnose that please? BTW, I disconnect the oil sensor socket from the sensor and the light still is on.

 

You sure somebody hasn't tried to put a small block Chevy in it some time or other? Cause that sounds like the kind of mess you'd find behind that!😃

What color wires are on the oil pressure and temperature senders now? Time to unwrap the engine wiring harness, find the original blue oil sender and green temp sender wires, and make the necessary corrections and repairs. The CSM wiring diagram is your friend.

Look for an obvious newer tape wrap on the harness. My guess is whoever yanked the 425 out of its original home just cut the harness and then spliced its wires to your car's harness indiscriminately. I mean damn, how hard is it to match colors? A kindergartner can do that.

Are you starting to consider why the warning lights were left out? 🤪

 

You never know what happened in the last 50 years! Looking under the hood, looks like everything was replaced at some point with new parts - nothing is original. The wire going to the oil pressure sensor is green. Now that I have been driving it more I now have more serious braking issues so I am planning on taking it to my mechanic and have him look at that (and the wiring) - will call on Monday. I am considering a front drum to disc brake conversion where I communicated on another thread.

ha ha , you pay attention! As soon as I started the car, I noticed that the oil pressure light stayed on and I then realized why the bulbs were taken out. lol I did not even think to look for that when I bought it. I overlooked the whole warning light thing.

My hunch tells me that the TEMP light will go on if the engine is hot, but the check when in position 1 is not working (based on getting voltage from the ammeter and when I grounded it the TEMP light came on) The Oil Pressure wiring is not right altogether. Everything is all nicely wired and taped - hard to tell where the problem is when someone puts another engine in. The Oil light is now always on no matter what.

 

The "temp" light will not come on when the ignition is on and the car is not running. It should come on while cranking the engine (this is the test function). There is a wire attached to the ignition switch that does this. It temporarily grounds the circuit while the key is in the crank/start position. Since you said that the light comes on if you ground the wire at the sensor, the light must be good and the wire running to the sensor must be good. If the temp light does not come on while cranking, your issue is either with the wire running to the ignition switch or with the ignition switch itself. One thing to check would be that the body of the ignition switch has a good ground. You can do this from the front side where the key goes in. If the ignition switch body does not have a good ground, it cannot provide ground to the light while cranking. To understand how the lights are supposed to operate, you need to understand how the sensors work. On a car with gauges, the sensors vary resistance through a range of values. For cars with warning lights like yours, the sensors reach a certain point (high temp or low oil pressure) and change from an open to a closed circuit on the ground side (getting ground from the engine and applying it to the sensor wire). When you turn the key on, with the engine not running, there is no oil pressure so the oil light will be on. However, the temp sensor will not provide ground as that only happens if the temp gets too hot (the sensor has no way to know if the engine is running or not, just whether it has reached a "dangerous" temperature or not). This is why the test function on the temp light is only during cranking, otherwise there is no way for the light to distinguish between the engine running vs. not running with the ignition in the "on" position. As for the oil light, if you disconnect the wire from the sensor and the light is still on, you have a short to ground somewhere in the circuit.

 

Hi Loaded, thank you very much for your post - appreciate the level of detail. I follow what you are saying. You are right about the temp senor too it is supposed to go while cranking. The temp light does not go one while I normally start or operate the car. As I mentioned before, if I turn the key, the temp light will go on when I turn the key clockwise and have the wire grounded.

Yesterday, I grounded the temp sensor wire and started the car - while doing this the temp sensor light did go one while starting. This is new information. What do you think now? That would tell me there is nothing wrong with the temp sensor wiring but now the temp sensor itself is not grounded the circuit, right?

The oil pressure wiring is another matter like you said. I hope to bring to the shop next week. Thank you for your detail post! Made me think.

 

With the temp light wire grounded the light will stay on at all times except when the key is off, same for the oil light.

 

To clarify, when I ground the temp sensor wire, the Temp light goes on while I start and while it is running and does not turn off unless I shut off the car. When I connect the temp sensor wire to the temp sensor (normal connection) and repeat the test, the light does not turn on while starting or running. Not turning on while starting is not good.. '

So I think I get it. When connecting the wiring that I have normally, while starting the car, the temp sensor wiring (the wiring that checks that the light works from the ignition) is either not wired correctly or at all thus does not ground so the Temp Light does no illuminate while starting. The wiring that connects to the actual temp sensor is hot. Because I checked that the wiring that goes to the temp works when grounded, the Temp light may very well illuminate when the car actual overheats, but will not know if the light is working beforehand because the ignition to the temp sensor wiring is either not working properly or not present. Perhaps something happened when the previous owner installed the 425 engine. Everything under the hood looks new-ish.

When wiring normally, the oil light on stays on while running or starting or whether I connect the wiring to the oil pressure sensor or not.

Thank you for your posts. I think I understand what was going from a combination of these posts and looking at the wiring diagram

 

Does the temp light come on in the acc position? If your oil light wire is left unhooked and not touching ground with the key on, is the light lit when the engine is running?

 

In the ACC position, whether the OIL / TEMP lights are grounded or not, only the GEN light illuminates.

The OIL light illuminates while in ON (which is running) position or STARTING position whether grounded or not (does not turn off when running when grounded or not)

The TEMP light illuminates in ON (which is running) position or STARTING position only while grounded. Does not shut off when running while grounded. Does not turn on while not grounded during regular operating engine temperature. (Note: The TEMP light may illuminate when not grounded and wired normally if indeed the car was overheating but obviously did not overheat the car)

The GEN light functions as it should in all positions.

 

You are so close to understanding. Both the temp sensor wire and the "ignition check" wire provide ground (-) to the light, neither one is hot (+). If you completely disconnect the wire from the temp sensor so that it is not touching anything, the light should still come on while cranking the starter. This is because the ignition switch is providing an additional ground (-) to the light separate from the sensor wire. Hopefully this does not add more confusion, but think of it like the door jam switches that control your interior light. If you open the driver door, the interior light comes on, if you open the passenger door the interior light comes on, if you open both doors the interior light comes on. This is because each door jam switch provides a separate ground (-) to the interior light. If the engine is too hot (temperature, not + vs.-), the temp sensor provides ground (-) and the temp light comes on. If you are cranking the engine, the ignition switch provides ground (-) and the temp light comes on. Again, I would start by checking that the metal part of the ignition switch has a good ground. The dash housing is plastic so if the metal strap that the ignition switch goes through is not giving it a good (-) signal, the ignition switch will not provide ground (-) to the temp light. The temp and oil lights are on the ignition circuit so they will not come on when the key is in the ACC position. The oil light should ONLY get a ground (-) through the pressure sensor. When you unplug the wire to the oil pressure sensor and the light stays on, that means that there is a short to ground (-) somewhere between the pressure sensor plug and the pin on the cluster (it is even possible although unlikely that the short could be on the cluster circuit board itself). This short can be anywhere inside or under the hood. To start you search, I would turn on the ignition so the oil light is on (car not running). Then unplug the oil pressure sensor. After that, start gently moving the harnesses around (under hood harness and under dash harness) while someone else watches to see if the light goes out. If you see the ight go out while you are moving the harness that will be the area to start looking for the short. I hope this helps.

 

Hi Loaded, thank you for your post - very clear an informative. Great analogy with the door lights. I also related this analogy with a visual I had after reviewing the wiring diagram in the service manual.

Some clarifications first. When I mean that that the temp sensor wire is "Hot", I mean that only when my car has its key in the ON or Starting position, electricity has the potential to go toward the sensor. This does not necessarily mean that the circuit is complete just that electricity has the potential to go toward it. Kind of like if I had one wire connected to a battery (but not grounded) as compared to another separate/unrelated wire just laying on a kitchen table not connected to anything. I needed to communicate this fact to negate that the temp sensor wire was dead in all key positions. I confirmed that the temp light works after grounding it. I also did not mean that the temp sensor wire has electricity while the car is off.

I attached a copy of the Warning Light section from the Owners Manual. To be clearer, and I was little incorrect prior, the temp light is supposed to go on when starting the car or when the engine is indeed running excessively above operating temperature. The oil light is supposed to go on when the key is in the ON position or when the oil pressure is indeed low. (The ON position is when one turns the key one position clockwise without starting the car). So we were both a little off, but difficult to communicate everything on the thread.

What is clearer to me now is that the temp sensor wiring has nothing to do with the check-warning light process when starting the car. Thank you very much for the enlightenment! Now that I am straight with that, I have to figure out why the ignition is not grounding the temp-check-light circuit while starting the car. Thank you for the ideas regarding the ignition switch and metal strap. I saw behind the switch when I put in the dash light bulbs. I need to re-look at it. Not sure I know what you are talking about regarding the metal strap. I hope it is something like that versus that the car is not wired at all for the temp-check light as the car had a renovation and not sure they replaced the wiring for that.`

Thank you also for the clarification of the oil light and how to find out where it is incorrectly grounded. Now with you post, I can visualized why the light is on while the car is running. The oil light does illuminate while the key is in the ON position - that is correct per the owners manual.

 

" We were both a little off, The oil light does illuminate while the key is in the ON position - that is correct per the owners manual."

This is not new info. Re-read my posts. I thought I explained pretty clearly that the oil light will be on WHENEVER the oil pressure is low AND the ignition is on whether the engine is running or not (this would include when the key is turned on but the engine is not running as there would be NO OIL PRESSURE at this time). The problem is not that your oil light comes on when you turn the switch to the first clockwise position (on/Ign), the problem is that the light does not go off in this situation when you unplug the wire from the sensor. Again, unlike the temp light that has 2 separate inputs to make it turn on (temp sensor and ignition switch), the oil light only has one source to make it turn on (the pressure sensor) If the pressure sensor is unplugged, the oil light should not ever turn on as it has no possible source of ground. I am trying to be as clear as I can, but I think something is getting "lost in the translation"

 

Oh okay, my apologies, I thought that the oil light had two separate inputs like the temp light and also possibly the GEN light. Your write-up was clear, I was not debating that - my reply was based on my interpretation of the wiring diagram in the service manual and your post. Re-looking at the wiring diagram it looks like the temp light and the gen light have two separate inputs but the oil light just has the one. But it was confusing at first because of the business and color scheme of the drawing. I could be wrong on the two-separate inputs for the GEN light but that is what it looks like to me. I would have had a backup wiring for the oil pressure but now looks like really have depend on that oil sensor.

I understand my oil light problem - I just need to know in to figure it out or explain to my mechanic. Thank you so much for replying and taking the time to clarify.

 

I have concerns about the wiring, esp that orange wire. I think whoever wired it somehow tied into the transmission control wiring which should in no way be tied into the oil light circuit.

Plus I'm always suspicious of any wiring repair I didn't do myself, unless I know beyond doubt the person is competent. I've known too many jackleg mechanics and electricians over the years.

Untape the engine harness, find out exactly what's in there and correct it. That way you know what you have and you're not at the mercy of someone else's POS- Previous Owners' Stamp.

 

Hi Rocketraider, Loaded and all. It has been 2 years but I have a little bit of an update. My apologies for the delay - they car has been running fine and just got frustrated with this and went on to other things , but I am revisiting now. Back 2 years ago, I took the 442 in to have the brakes fixed and they were fixed, but the mechanic didn't fix the temp and oil light problems. He doesn't work on electrical so I am just now circled back and re-reading these posts and seeing what I can do.

Firstly, I peeled back some of the black tape and the indeed I have a blue wire going to the oil temp sensor and a green wire going to the temp sensor (those other colors were just the last couple inches of a new connector).

As far as the Temp (or Hot light issue), according to rocketraider, I have the wrong type of temp sending unit (I have warning lights with a flat head temp sending unit). Rocket raider said I need a single prong type temp sending unit and that was consistent with Fusick as well. So I just ordered a new , single prong temp sending unit along with a new connector. I will see if what makes a difference after that comes in next week.

As far as the oil pressure light, the light stays on even when I disconnect the sensor. I know that must mean a short. I followed it some, and move the wires around and still have not been able to get the light out. I will still play with it tomorrow. Frustrated with that.

I also re-read Loaded68W34's posts and relooked at the wiring diagram in the Service Manual. For clarification, trying to understand how the temp light goes on while cranking and how the temp light goes on during operation from the wiring diagram. Firstly according to the CSM wiring diagram, there are 5 colors. Is these what these 5 colors are for from the ignition switch:

1) Bright pink (from the battery) - just 12 V to the ignition switch in the OFF position - this is clear
2) Purple - goes to the starter switch when in the ignition switch is in the CRANKING position?
3) Green: Is this the ignition GROUND?
4) Light pink: Is this the wiring for when the Igntion switch is in the ON (regular running) position?
5) Brown is Accessory (ACC) - this is clear

Did I get this right? Also if the engine temp is not hot, how does the temp light go off after cranking from looking at the wiring diagram? From the wiring diagram since there are two ways to ground the temp light, I am assuming that when the ignition switch goes to the ON position, the igntion ground is disconnected and therefore must go to the temp sending unit. In theory that makes sense, but it is not intuitive from the wiring diagram if I understand correctly. You have to know how what happens inside the ignition switch at each position.

 

By the way, looking back no one answered what the picture on the right is. I understand the left picture is of the fuse box by the drivers left leg, but what is the right picture and where is it located please?

 

The picture on the right is the bulkhead connectors.

 

Thank you Eric, that makes sense - that is on the drivers side connected to the firewall I believe where the left side goes to inside the cabin to the instrument panel location where the right side of the bulkhead connected goes toward the front of the car not sure where perhaps to the negative part of the battery cannot see where it goes as the windshield wipe reservior is in its way.