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30 Pontiac electrical issue

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All my electrical items have been working the way they are supposed to work until yesterday. After I cleaned the reflector on one of the headlights I pulled the light switch to see if I had done any good and heard the fuel pump start. It's supposed to and has been getting its power from the ignition switch. I shut the lights off, turned the ignition switch on and the lights came on. I should add that the car has a separate coil and not the original style. I also learned that I can get power to the ignition by pulling the light switch. The engine will start without the key on but with the light switch pulled.

I keep going back and forth in my mind on whether the light switch is faulty and is feeding power to the ignition or vice versa.  Thoughts? I hate crawling under the dash.

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Obviously the wire feeding the coil should come directly off the output side of the ammeter.  Someone somehow has the connected the headlight switch so that it feeds the coil, fuel pump and the fuel pump.  A wire should connect the ammeter to the light switch only.  Your electric fuel pump should be on it's own circuit and should be protected by a oil pressure shut off or at least a gravity safety switch.  Or just remove it altogether and use the proper pump on the engine.  If your electric pump doesn't have a safety switch you could be looking at a fire if there was an accident.

 

Take a couple of tylenol before getting under the dash.  Then you don't have to wait for the pain killer to kick in.

30 wiring.jpg

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Posted (edited)

When I rewired my '32 (same switch as '30) I made a diagram of the switch connections based on the three positions of the lighting switch.  I have attached a photo of my notes.  You will notice some numbers penciled in and they are not voltages but resistances I measured and are for my information and the particular switch in my car.  Hopefully this helps.

 

I will weigh in on the electric pump too.  Tinindian's warning is very valid in my mind.  I strongly think that electric pumps are not necessary in split head Pontiacs (at least from '28 on with mechanical pumps).  The main complaint is that if the car has been sitting for a while it cranks more than people are comfortable with while the carb bowl is refilling.  There is a very simple solution to this and that is to drive/start the car more often.  Once the car is started and warmed up you only need to touch the starter to get those engines running. 

 

I just went from a non-original coil to one that is the original style in my 6-30B  and found that using the selfie position of your smartphone was a great way to trace the wiring under the dash.  Getting some photos of what is there and chasing the wiring without having to crawl under the dash saves time.  You have to take quite a few photos to get all the detail in focus but it is much easier than the alternative methods.

 

I have found that head under dash, butt on seat, and feet resting on the B pillar (no shoes of course) is the best yoga position for the Series 6-30B under dash work.🤪

Switch.jpg

Edited by 32Pontiac6 (see edit history)

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I agree with Tinindian.  Someone screwed up your wiring. 

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Thanks for all the advice and I'll look more closely at my car but the key here is why had everything worked as it should one day and malfunctioned the next. The fuel pump is on it's own circuit. 

 

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Check that the body, frame, and engine are grounded solidly together (could a ground strap somewhere have failed?).

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To get this straight you turn on the ignition switch and the lights turn on. You turn on the headlight switch and your fuel pump turns on. And all you did between this happening and everything working correctly was clean the headlight reflectors nothing else?

 

Those switches when wired correctly have nothing in common.

 

I would check to see how the wires were run out from their respective switch. If they are in the same protective loom or tape they could be melted together. This could also explain your lighting issue if it was not solved by cleaning the reflector.

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Well what was the problem.???

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Sorry I've been so slow responding.  I hope I can describe this logically. Apparently I had a situation where I was cross feeding the ignition to the lights and the lights to the ignition.  The car has been wired and I have been moving it around the shop under its own power for about a year.  I didn't have the headlights mounted or the tail light wired into the lamp until recently.  I had checked the head and tail light wiring with a multi-meter and everything functioned.  The problem didn't surface until sometime after the head and tail lights were installed but not immediately.  The fuel pump did not start with the light switch pulled nor did the lights come on with the ignition switch.  I used the wiring diagram and a little logic, changed a couple of wires and now it's working as it did.  I'm wondering if there could be something inside the switch that caused the problem? 

 Not a very good explanation but it honestly had been behaving as I originally described it.  It's now fine again.

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