Okay, Question...
I purchased the BWD S369 switch and either I'm being stupid (which is always a possibility), or something is amok. First, I'm using aftermarket electric gauges and do not have an oil light on the dash, just the pressure gauge. According to instructions, I have the S369 switch installed with a tee fitting. I have attached a fused lead from the alternator post to one terminal on the switch and another lead from the 2nd terminal to the positive side of the choke. Since I have no oi warning light, the 3rd terminal is unused.

If I understand the operation, I should only have power out to the choke when the engine has oil pressure. However, I have power to the choke even when the key is in the off position. What am I doing wrong?

 

I added pics to show installation... wire to the left post is the power from the alternator, wire on the right is lead to the choke. Right lead is constant hot.

 

The diagram doesn't seem to make sense.

To work correctly, it should get switched 12V, not constant hot. The diagram shows a constant hot.

If that were the case, and if you swapped the "to oil light" and "to choke" it could possibly work as you described.

Start the car and check if you have power to the choke. If you do not, then you could switch "to oil light" and "to choke" wires.

Then you would correct the 12V supply problem.

Otherwise, I can see why you are puzzled.

 

What's the voltage reading on that terminal? Perhaps you used the wrong one?

 

13+ on both terminals... if I switch the leads, I get the same result. Voltage on the 3rd terminal is goose eggs no matter which other terminal I power...

 

My understanding is that the terminal shouldn't be hot until there's oil pressure at the switch. I'll try that, but all that I have seen shows using the opposed terminals for power and output. Have you seen the post the diagram came from? If not, take a look at it.

Thanks for the response.

 

So you're saying the switch is not switching and you have a power splitter. Sounds like a faulty switch.

 

I'm gonna try a different brand of switch to either rule out the faulty switch or to fix my problem. I was searching for reassurance that I wired this the way it was first shown in Joe P's initial post. Electrical work isn't my forte so I'm always glad for guidance.

 

Same thing happened to me, wired it up but never checked, two days later dead batt...hmm last thing I worked on was the choke so then I checked it, yup 12v to choke all the time, I bought another switch but haven't swapped it out yet. I'll see if I can find the two brands I got, IIRC I homed the second switch and it appeared correct, i.e. No continuity between 1 n 3 terminals w no pressure.

Edit:
First switch was standard ps127

Second switch was airtex 1s6552 this one is not tested as working yet, the ps127 was how you described yours.

 

Thanks Retro... That's exactly what happened to me! I had the car hooked up to the battery tender and noticed I was at 60% and charging. The last thing done was the choke, so I felt the housing and it was hot.

I've been doing a little research this AM and am going to try a different switch. Since I have no oil warning light any more, I don't need the 3rd terminal. I'm going to try a PS115, which shows to be a normally "open" 2 post design. I'll post results later today...

 

The specs on the PS127 switch are the center terminal (designed to operate the OIL idiot light) is normally closed to case ground with no oil pressure and opens at 4-6 psi. The outer two terminals are normally open and are connected to each other (and nothing else) above 7 psi. The PS127 has been functioning in my 62 F-85 for about seven years now with no issues.

The BWD S369 is SUPPOSED to be an interchange for the Standard Motor Products PS127. I cannot vouch for the accuracy of that interchange; I only repeat what is listed in the catalogs.

It is VERY easy to test the functioning of the switch with an ohmmeter. Pull all the wires off the switch. With the engine off, you should read open circuit (infinite volts) from either of the two outboard terminals to any other terminal and also open circuit to ground. You should read zero ohms (closed circuit) from the center terminal to ground (the switch case) and open circuit to either of the outboard terminals.

Now start the engine. You should read zero ohms across the two outboard terminals and infinite ohms from either outboard terminal to ground or to the center terminal. You should also read infinite ohms from the center terminal to ground.

If these test are correct, the switch is functioning as intended. If not, it is either bad or mis-boxed. There are identical appearing switches that are wired differently and it wouldn't surprise me if they got put in the wrong boxes.

As for constant hot vs. switched hot as a 12V source, it doesn't matter. The switch is open with the engine off.

 

It looks to me that your meter is set to DCV, not Ohms......?

 

You're right... I forgot to reset the meter when I took the pics. I already returned the switch so can't take another pic, sorry.

 

Slight correction. With the engine off you should read infinite ohms not volts.

 

Well I picked up the correct sending unit and all is well, dash light works, choke works. It is nice to get something completed. I also threw in a set of KYB shocks all the way around. I'm waiting on the rear sway bar. At that point having gone through the front and rear suspension and steering gear I will see how it is suppose to handle.
Thanks for the help,
Steve

 

Hello. Great thread. I have a 1971 Cutlass with 350 4bbl Rochester. I replaced the divorced choke with EC. The oil pressure switch has been replaced with an oil line running to the gauge under the dash. I would like to use the other method to connect the choke to but cannot find the relay with the 85, 86, and 87 connectors. Also there appears to be a vacuum hose behind the choke. What gets connected to that? Thank you.

 

Any common 4 or 5 pin relay at the local parts stores are wired the same. Pin 85 and 86 are to the relay coil (some of the OEM relays have diodes across the coil pins to prevent voltage fly back so polarity is important) pin 30 is the common. Pin 87 is normally open across pin 30 and 87 with the relay off. Pin 30 and 87a will show continuity with the relay off. Turn on the relay, 30 and 87a will open, pin 30 and 87 will now have continuity.


watch this, a picture (or video) is worth a 1000 words

 

There are a million of these in any auto parts store.

 

Thank you for the reply. I thought there was already one in the car installed for the alternator or did I misunderstand the original post from several years ago. So I will have to buy a 20 amp fuse, and blue and green wire. What is the gauge of the wire? Is there a standard color coding similar to house wire, ie 14 gauge is for 15 amp circuits, 12 gauge yellow is for 20 amp circuits?

 

No, there is noting already installed unless you have a 1980s car that came from the factory with an electric choke.

 

I bought all the parts. Now to implement it and see if the car will start.

 

Thank you for the video. I notice in the video the ground is number 85 where in the diagram 86 is the ground, 85 and 86 are reversed. Does this matter which one is the ground and which one goes to switched power?

 

Here is the latest update. I found where the Oil Pressure switch was located thanks to this thread. The original switch was there but the wire had been cut since the car now has the Oil Pressure Gauge instead of the light. I purchased the PS127 switch and installed it.

 

I wired the choke up per the diagram. With the car not running I get 13 volts at the terminal going to the alternator. The other side going to the choke is zero volts. When I try to start the car it fires for about 5 seconds then stops. Is there something else that I am missing? I attached some photos of the carburetor I purchased a couple of years ago. Did I miss anything? A new fuel pump was installed at the time. There was a rubber hose from the pump to the old carb. I purchased the metal line as you can see in the photo plus I replaced the linkage since the one on the car was some kind weird setup. Also, new fuel tank float, etc, and lines running to the vape box behind the rear seat. Is there something missing from the rear of the choke? Thank you.

 

the threaded part at the rear of the choke is for a hot air choke. Your carb now has an electric choke.

 

Retro Ranger,

Thank you for the information. I presume that means I do not have to do anything with it.

 

eh maybe.

I just capped mine off to keep any debris out of it. I also capped off the ports on the back of the carb. The cavity on the intake manifold just below your choke can be blocked off too just for aesthetics

 

I will look for some plastic caps for the choke. I think I have some in my box of AC parts. Thank you again.