So after 4 months of waiting I finally have a completely rebuilt rocket 350 !!!! While it was being built I installed a rallye gauge from the Tic Tac Toc option for the 70/72 cutlasses. So with the Gauge the houses the gas gauge. I have working needles for the gas level, and the oil pressure, but not the engine temp. I have continuity to the gauge from the sensor. When I got home I checked the teminal Repatterned from the Stock ( idiot light ) to the Rallye gauge. I installed new pod lights. Gas and oil needles are illuminated but not temp needle. When I turn the key to accessory the temp needl sets to the center. But when I brought the car home from the shop temp never registered. 1/2 hour drive back roads and highway drive. when I got home I pulled the gauge and checked the green wire of the temp sender unit, cleaned the treminal and re inserted it into the connector. Will run the car again tomorrow and see it the gauge starts registering. But still have the pod light not working. Tried 3 bulbs, cleaned the contacts and the circuit board. no go. Could it be a bad socket ?

 

Did you replace the idiot light temp sending unit with the correct sending unit for the gauge?

 

Hi Fun71,
I talked to the mechanic this morning and yes he ordered the correct sending unit for the Manual gauge. T56? I believe that is what he said. When the ignition is in the accessory position the temp needle does set at the center of the gauge between hot and cold. So possibly when I cleaned the connector that solved the issue. Need to let the car warm up today. Was trying to do it in the dark last night. But still have an issue of no illumination at the part of the gauge.

Thanks for the input, Tony

 

Hmmm, I remember the temp sensor setting/bottoming out to cold and the oil topping out to H when the key is turned. Perhaps someone else can check on this..

 

So I still am having issues with my Rallye Gauge. After cleaning the terminals and contacts and checking the wire I added two additional ground wires to the back of the gauge pods. So now the current situation has not changed. The Gas gauge and Oil pressure gauge work fine. When the key is turned to accessory position the Gas gauge registers and so does the Oil pressure. But the tem sets down at C. But also at times the temp sets at dead center. But when the engine is turned over the temp drops back to C. I drove 1/2 hour on the turnpike and the temp never climbed from C. Also the needles seem to fluctuate while driving (bounce around) Gas and Oil. More the gas gauge. When I had bought the Gauge Not Reproduction, I had someone clean it and lube it but he said he did not do any calibrations on it. Could this be the issue with the dials bouncing and temp gauge no registering? Luckily the engine build was done perfectly and even after a 1/2 hour drive between 55/70 you can put your hand on the upper radiator hose. So the temp is running at its speced 180/185 degrees. But it would be nice to have the working temp gauge. Any help and thought would be appreciated.

Thanks !

 

Did you properly reconfigure the wires in the rally-pak gauge pod connector? If not, it should look like this for gauges.

 

Thanks Tom ! I did the swap based on a guide a freind sent me for the conversion from idiot light to Manual ( Rallye Gauge ) but now I need to go check again because I think there is a Black wire in the harness which I mistook as a mis spelling on the diagram ! Thank you for the picture That will really help ! I know the Lt. Green is the water temp sending unit wire.

 

Your image is from the Chassis Service Manual. It matches the location of each wire in the color image I posted.

 

The oil pressure should not register any pressure since the engine is not running when the key is in the accessory position.

 

Hi Tom,
I haven't taken out the gauge yet but thought a quick video of operation might help. After engine is running for a while the temp gauge doesn't register. This was even after driving for a half hour on the PA turnpike at 65 last weekend. Mechanic said it had voltage ( OHMs )from the sender to the firewall. But he did not take the gauge out interior wise to check the light green wire from the firewall to the gauge.

 

Have you verified continuity from the green wire at the gauge connector to the connector at the sending unit?

 

Hi Toms cutlass.
Thank you so much ! I pulled the gauge and sure enough i did install the ( Black ) wire into the ( Blank ) socket location and temp gauge is working now ! So now my question is why is there a black wire in the gauge harness if it was never to be used in either configuration? Is that there for a different gauge configuration in a different car? Or is it supossed tobe connected to something else even though the terminal end is clearly designed for the plastic gauge connector. But any ways it's all good. Ran the car for about 10 mins and the gauge climbed as the engine warmed. For one moment the needle dropped down to cold but then jumped back up to is location.

 

Hi Matt69olds.
Got it figured out thanks to Toms cutlass. The harness has a black wire in it for some reason in both configurations and I took it as a missprint of the word "Blank" on the schematic LOL. So as soon as I pulled the BLACK wire out from the connector temp gauge worked ! But as I said to Tom. Why is there a black wire in the harness if it isn't meant to be used in either configuration for either the idot light gauge or manual gauge?

 

Great news! Congratulations! (You could remove those extra grounds too now, if you want.)

One more thing, I noticed in the video that your temp needle pegs to "H" when you turn the key to start the engine. Did you know that you can (should) disconnect the green wire down on the ignition switch on the column to eliminate the needle pegging? There is a thread or two about it. Easy to do and suggest that you do that to prevent damage to the temp gauge needle.

 

Just saw this thread. I also had problems with my Rallye pac, but a different situation that required the dark green lamp test feature from the original idiot lights to be disconnected from the starter switch. I noted that your gauge cluster only illuminates the GEN feature when starting (same as mine). Makes me wonder why the BRAKE doesn't light up too. It does when I put on the E-brake. Maybe that's part of the wiring change from idiot lights to rallye?

 

I don't see a "black" wire in my color photo of the order of the wires in the gauge connector or in your chassis service manual schematic. Not sure what you have going on there?

 

That's correct. When converting to a temp gauge, there is no need to test for temp bulb (idiot light) failure at start up. With gauges, since there is no volt gauge, the GEN bulb lights on startup as a test of that bulb (idiot light). The BRAKE bulb is tested by applying the E-brake so it doesn't light up on engine startup.

 

Perfect! Thank you.

 

Yes, this is to prevent the temp gauge needle from pegging on start as I noted above. I've read that aftermarket gauges, in fact, require that green wire to be disconnected or the warranty is voided. (I have OE Rally Pak.)

 

Yup, got that one solved too. Mine are also OEM gauges and tach/clock. Gotta do some troubleshooting on the clock/tach as it currently has decided to go tango uniform. I see gauge rebuilders charging upwards of $500 just to rebuild the tach. That's crazy.

 

Toms cutlass, Hmmm thanks I will recheck that since when I did the video it was before I removed the black ( BLANK ) wire ! LOL I didn't notice it doing it after I corrected the wire issue, but will check that tomorrow. Any thoughts as to why there is a black wire in the gauge harness? Or is it there to just mess with our heads?????

 

Allan R, That is the same as the idiot light gauge my parking brake light only came on in the gauge when the parking brakes was on. But good point another thing to check to see tomorrow if the brake light lights if I have the parking brake on.

 

Tom. my Rallye gauge is OE not repo. but good info to know I will check the gauge tomorrow to see if it pegs or not.

 

The black wire is possibly there as a spare. Not for you to use, but for the instrument panel designer to use back in the day. They may have designed something else, then aborted it and it was too late or costly to change the wire harness. Or, something was intended to be planned that never took off. I wonder where the 1972 year check seatbelt light power is from.

 

Even if it's not a repro, you should disconnect that green wire for the temp idiot light. If you need further guidance on which one it is, come back and I'll describe it and where it is located.

 

I checked the seven (7) rally-pack gauge wires, the gauge wire connector, and the general area behind the entire gauge cluster on my '70. I find no black wire, nor any black wire with an end similar to the ends that plug into the back of the gauge connector. The main harness wiring (of which the gauge cluster is connected) is OE on my car, with no after-market modifications or custom one-off splices, so it is all original. (The other wire harnesses on my car have been replaced with OE replacement - forward, engine, courtesy lights, intermediate, fuel sender, and rear/trunk.) I don't know how long you've owned your car, but it is quite possible that a prior owner added a black wire for some unknown reason, but that's just a guess. Also, I didn't find any black wire for the gauge cluster in the Assembly Manual or Chassis Service Manual.

I'm not clear about where on the gauge wire connector you plugged that "black" wire in to. There are only eight (8) open positions on the gauge connector for a wire to be inserted. (See images in your and my posts above.) The "BLANK" position on that connector is just that; it does not have a hole in it allowing for any wire to be plugged into it.

EDIT: I think I answered my question. You plugged the black wire into the slot marked #7. Note that the #7 slot for idiot lights set up is the temp gauge green wire. That likely explains why you had the issue with your temp gauge not registering.

 

Hi Toms cutlass,
So after work tonight a hopped out to the car and YES the temp gauge does jump up when to start the engine as you had mentioned. So my question now is when you disconnected the temp gauge green wire at the ignition switch. Did you physically disconnect the ignition switch and remove the wire from it? Or did you just cut the wire and cap it. Just so I'm correct the ignition switch is the horseshoe shaped switch under the dask mounted on the sterring column correc?

Thanks, Tony

 

no that is the neutral safety switch, sitting at the bottom of the column, kind of crescent shaped. The ignition switch is further up the column and rectangle.

 

Tony, as PatL stated, that crescent-shaped module on the top lower end of the steering column nearest the firewall is the neutral safety switch. The ignition switch is up the column about 6" from that neutral safety switch. The connectors and wires plugged into the ignition switch face the passenger side. Some CL members say they've had to lower the steering column to get at the green wire. I didn't. I simply removed the black connector in the side of the ignition switch that contains the green wire (closest to the firewall) which made it easier to access. (Getting the black connector out of the ignition switch is the hardest part. The connector has a little squeeze retention clip that holds it into the ignition switch.)

It is the green wire in the black connector (not the white connector). I believe there are 2 or 3 wires in that black connector, one of which is green. Rather than cut the wire, I removed it from the connector by sliding a small screw driver in the back side of the connector to back the wire out of the connector. Then I taped the end of the wire and marked it with a tag indicating what the loose green wire is for and from.

If you need an image of the connector, let me know and I'll take and post.

 

Toms cutlass,
Thanks once again for the input ! I could not have figured this out without your help. First to address the black wire in the harness. It is possible that the harness was from another car since I did locatate an original underdash harness from a seller on Ebay. But he did state it was a 72 Cutlass. But who really knows, I couldn't pass it up since it was in perfect shape and still had all the sockets and bulbs in it including the optional courtesy light package. And at $75 shipped I couldn't pass it up. My original harness had been hacked up, I sold original harness to someone that needed some good parts from it. Secondly thank you for the additional info about the ignition switch. My cutlass convertible is equipped with factory A/C. Do I need to remove the lower duct valance to access the ignition switch? And I would welcome any pictures and process of detaching the switch from the column. I purchased a terminal tool kit ( well worth the price ) so I do have the correct tool for all different terminals. I also purchased a Packard terminal and connector kit so if needed I can replace any clip and plastic cover when needed. So it is pooring rain here in PA and my car is not garage so I'll be holding off on this project till after the weekend. Gauge should be ok till then. I only plan on starting the car about 8 times over the weekend since I am doing two shows this. Tomorrow is a turnpike drive to the show , so it will good time to confirm the temp gauge is functioning properly.
Once again , thank you for all the help regarding the temp gauge ! You've saved me alot of aggrevation.
Tony

 

Tony,
Follow the orange wire to the black connector. (See images.) The green wire (temp check wire for idiot light) is in that black connector. Sure, you can cut the green wire (and tape it), or remove the black connector (you can see the clip on the left side of the connector in the image, push that up and pull the connector out of the ignition switch). The green wire is removed from the back of the connector by bending the "ear" of the terminal end of the wire with a small screwdriver and it slides out. You can see the green wire in the images (just above the orange wire) with the white wire identifier I placed on it for future reference so there's no loose unidentified wire there.

Note: To remove the black connector, I disconnected the "piano" connector of wires that run from the turn signal switch under the steering wheel down the column that connect in front of/below the ignition switch. That turn signal switch "piano" connector is partially seen at the bottom of the first image below with a line of wires. This allowed easier access to the black connector in the ignition switch.

 

When I did my conversion I didn’t want to cut the wire or just tape the end up. I removed the terminal from the connector then I put the terminal in a extra single terminal connector that I had. Now it’s just us unplugged wire with nowhere to connect. If you don’t have an extra one they are pretty cheap, and look better the electrical tape or heat shrink.

https://www.ebay.com/itm/DELPHI-PACK...sAAOxyM89SbAVc

 

Well I thought I was out of the woods with the temp gauge not registering. Was working fine after I removed the black wire from the rallye gauge connector. started the car and temp needle rose as the engine warmed up. I do still nee to remove the green wire from the ignition switch. But have been running out of daylight before I can get to it since I don't have a garage to work in after dark. This morning I started the car and the needle spiked as suspected and instantl droped down to C as it should. But then it never left the position even after the can warmed up and I drove it on the turnpike for a half an hour. WTF ! I am so friggin' frustrated with this issue ! Here are two short videos for referance ! First one is at start up. Here is the link sorry tried yo upload but keep getting a error notice for upload saying invalid URL. Second short vid is upon shut off.

 

I have a '70 no A/C, but I assume you'll need to remove the A/C duct on the driver's side for easier access to the ignition switch and black connector with the green temp wire.

 

Well, that's disappointing. These electrical gremlins can be pesky, but don't lose patience.

I'm beginning to think your temp sender unit is faulty. I know you said you tested it, but I recall guys here on CO have had issues like yours with temp gauge senders. Just because you are getting continuity to the sensor doesn't mean it's the correct sensor. I know you said your mechanic ordered the correct sensor, but is it the correct one?

I'm now going back to your earlier posts to see if there are any other clues. You said earlier that you "installed new pod lights. Gas and oil needles are illuminated but not temp needle." The video shows all gauges are lit. So is that problem solved and how did you solve it?

Also, you said "the needles seem to fluctuate while driving (bounce around) Gas and Oil. More the gas gauge." Is the gas gauge still bouncing around? I know you said you added grounds to the gauge cluster. All of the incoming wires in the pod are positive (+) with the metal pod being negative (-) ground.

You also said: "When I had bought the Gauge Not Reproduction, I had someone clean it and lube it but he said he did not do any calibrations on it." Was it a reputable place that cleaned and lubed it? (I don't know what clean and lube needle gauges would mean; don't know if that is "normal" to do, I've never lubed my gauges, but I have painted the needles to stock fluorescent red-orange color and painted the inside of the pod.)
Do you know if the temp gauge ever worked? I'm not aware of any calibrations on the temp, oil, or gas gauge needles inside the pod. (There is a calibration for the tachometer needle on the tic-toc-tach, if you had it.)

 

Tony,

One more idea ... what is the condition of the pins on the back of the gauge pod that the wire connector plugs in to? Those pins can become loose and not make solid contact with the printed circuit board. The pins are press fit with tiny claws on the other side of the circuit board. If the claws are not making good contact, that would explain intermittent working of the temp gauge. The gauge pod circuit board can be carefully removed and the pins checked for solid contact with the back side of the board.

 

Gremlins have been busy ! So just to frustrate me I started the car to warm it up to go out to a show this morning. Turned on the heater to defrost the windows since htere was frost on the windsheild. Hope into the car and headed out to the show after the car had been running for about 15 minutes.As I headed down the road I looked down at the temp gauge and it was between C and the 1/4 hash mark. About 5 minutes later I looked down at it again and it was between the 1/4 and 1/2 hash marks ! So now it was working again. The drive home was about 20 minutes . And so ctarted the car after the show eneded and needle was just above the C and by the time I got home it was once again just under the 1/2 hash mark.So now seems the gauge is working again. We'll see what happens Tuesday morning when I go back to the mechanics for an oil change.

 

Another thought ... you said you had your engine rebuilt. Did they burp the cooling system? By that I mean, there could be air in the cooling system and the temp sender must be in coolant to get a correct reading. If you are low on coolant (antifreeze mix), the sender may not be immersed in the coolant. Check your antifreeze level - WHEN THE ENGINE IS COLD.

 

Hi Tom,
Thanks, for all the input, When the engine was done he did pull the radiator also. So there could be a possibility that ther could have been air in the tank. This thing has been crazy, one day working next day not and now working as should be again.So I will seewhat it is doing on Tuesday when I take it back down to the shop for oil change. I'm hoping tomorrow isn't to crazy and I can get back early enought to pull the Ignition switch and pull the black connector so I can remove the green wire from it. Thank you for all the info for my adventure under the dash !. I will keep you posted of my progress.

 

The absolute easiest most fool proof way to get all the air out of the system is to raise the passenger front corner of the car. Leave the radiator cap off overnight. If the coolant level drops, that means coolant has naturally flowed into the places once filled with air. No mess, no questions, simple gravity.