Electric gremlins

[Doug&Deb]

Driving to work this morning my lights kept blinking off momentarily. The amp gauge would drop to full discharge when this happened. Also my wipers don’t work. Not sure if that’s a coincidence or not. Where to start looking? Bad battery? 

[Barabbas]

I'd start looling for A short.   You have a 30 amp circuit breaker that automatically resets--I expect this is the cause of your lights blinking on and off.  It's located behind the instrument panel near the ammeter.  So the circuit breaker is "saving" you from a fire.  Turn off you lights and see if the wipers continue to work--if they do, the short circuit is in the lighting circuit

[John Reddie]

I would look for a wire or wires that are worn and possible shorting out briefly. Put on you lights and jiggle the wires around to see if you can recreate the problem. The full discharge that you mention suggests a strong voltage draw. Best of luck.

John R

[Doug&Deb]

Thanks, I’m going to load test the battery and check if the regulator is going. Then I’ll start checking wires. Until I had the engine rebuilt this was the most reliable car I’ve had. Since then nothing but problems. Oh well.

[Silverdome]

The dimmer switch is a likely culprit. I've had all my lights go out because of a bad dimmer switch.

[derbydad276]

my 53 is doing the same thing... and I just ordered a new light switch from bernbaum ... I guess ill order a high beam switch too 

[Young Ed]

My coupe is older and has a fuse rather than a circuit breaker. When I had an issue with my lights going out frequently it was due to a wire that got out of place. Eventually the clutch pedal wore through the insulation and from then on anytime I put the clutch in with the lights on POP fuse blown. 

[Plymouthy Adams]

as I stated in yet another current electrical thread....these old harnesses are at the very end of their useful lives 2 decades ago.....a hand over hand of the harness and all connections is job 1 on most any electrical issue......I say this as many do not break apart the distribution and trouble shoot circuit by circuit.  It is not a hard task but you do need a few electrical testing devices.  Hopefully with the hand over hand and a good set of eyes, many can often find the problem.  Chaffing is often the ugly culprit.  Pinching a harness during that LAST MAINTENANCE is most always a culprit if it just happened after you did some work in or about the wiring routing.  

[MarkAubuchon]

had this happen on my 49, Id found mine was a worn wire at the brake light.

[Doug&Deb]

I agree Plymouthy, I need to troubleshoot the entire electrical system system by system. That requires two things that are in short supply with me: time and skill. I’ll try to find the time. Can anyone give me an idea of how to get started? Problems like this usually caused me to sell a car. Since that’s not an option I guess I’ll have to figure it out. Any suggestions will be greatly appreciated.

[maok]

Well, seeing as your lights are flicking, if it was me, I would start with the lights and its circuit.

 

I would check,

• Light globes (front and rear), their sockets and connections,
• Wiring to the lights,
• Light switch and dimmer, if it has one.

The amp meter showing a discharge indicates there is a short somewhere.

 

[maok]

I had a similar issue on my '28, but this was a constant discharge of about 10amps. It would only happen when the lights were switched on. After disconnecting each light plug one after the other, the left front headlight was where the short was. The parking light socket and its spring were rusted and shorting on the power wire. 

Be systematic with your diagnosis, otherwise it will  test your character and soul.

Edited May 9, 2019 by maok

[Doug&Deb]

Two things I don’t understand, how the wipers are connected to the problem and why there’s a crackle of static in the radio when the amp gauge flickers. I still think the problem is under the dash, just not sure where yet. I can’t replicate the problem when I’m working on it which is really frustrating. 

[ptwothree]

Stick a camera/phone up under the dash an take a pic of the back side of the instrument panel.  Easy way to check the condition of the wiring around that area.  Rotten wiring on a 60/70 year old car is standard equipment.

[Doug&Deb]

Good idea. I’ll try that also 

[derbydad276]

my 53 was doing the same thing ... turned out to be the power wire to the brake light switch ... grounding against the frame