JC3

70 Challenger fresh resto. No front turns. When lights are on, radio will blink off & on, headlights will go out & back on and Volt gauge will jump up & down. On test drive all worked good untill it got dark and needed to use lights. Any help would be great !!!!
THANKS
Jim

blue 68 gts

Could be a faulty voltage regulator.. Simple test is to bypass it and see is everything works with no issues. But don't do it for a long amount of time (say, 10 minutes max). The battery will start bulging.


Could be a ground issue.. Any fuses popping? Could also be a short to power.

JC3

Thanks for the info. It is a new reg from yearone. I will try to bypass it. All fuses are good. Short to power ?? I am a body and paint guy, do not know a ton about wiring.
Thanks, Jim

440roadrunner

I sure don't see how a bad regulator can cause this problem. You may have multiple troubles

Front turn signals? Do the rear ones work?

You should be able to probe the connector where it comes from the column and see if you have juice, or better yet, do the dash turn indicators work? If they do, you either have a wiring problem out front, bad grounds or bad bulbs

The other stuff could be a combo of things.

Bad connections in the bulkhead connector, which are getting to be a royal PITA on these cars.

Also, there's a big splice in the under-dash harness where the main feeds come in and out and hook to the ammeter, and these HAVE failed.

The ammeter itself can be a problem.

It may or may not be caused by something else, but the headlight switch main circuit (headlights) has a breaker right on the switch. IF the switch goes bad, or the connections get bad, things can heat up and trip that breaker on/ off. But the breaker ITSELF can become weak and do the same thing.

DO YOU HAVE a wiring diagram?

Barfly

Well here might be an idea........

Try pulling the fuses on all the offending or effected equipment.
Then replace them one at a time, trying each circuit for correct operation. You may find that a short in one circuit is effecting many others.

I don't know, but it maybe worth a try.

Joe.

blue 68 gts

Explain.

440roadrunner

I have a better idea. You explain how it CAN

I can't think of how a bad regulator would cause this, unless it is faulted so as to "full field." But the OP did not mention that the headlights are obviously over-bright, and IF that's what happening, "bypassing" the regulator sure as heck is not what you want to do, because that would cause a full-field (full charge) condition for certain.

If it is NOT charging, the headlights would not "blink on off" they would simply be very dim, get dimmer, and if they got dim enough, pretty soon the car would not run, or crank. (Dead battery.)

scotts74birds

Well try it with the car OFF, and the voltage regulator will be ruled out! Rule of thumb with DC....If it dont work, check power. If it works weird, look at grounds! Barfly is also onto something! Some circuits with bad ground can also "back-feed" into others and cause symptoms that lead you away from the truth.
Case in point....Last week the wife borrowed a pressure washer from a friend and put it in the trunk of our 01 Sebring. On the way home she said it stalled, ran rough, gas gauge dropped to zero, check engine light came on [Lean misfire], park lights in the front came on, and the rear back-up lights were on! I scratched my chin for a few, and as the sun went down, I noticed the trunk light was dim. I also remembered the rear defrost didnt work last week. I took the washer out of the BUNGEE CORDED OPEN trunk! I closed the trunk, and the engine smoothed out, lights went off, fuel gauge started working, etc,etc. Still no rear defrost. That my friends, is what a bad ground can do! These are ALL separate circuits that share a common ground in the rear of the car. The fuel pump was affected by the bad ground and couldnt run right. The defroster was a clue because it needs more current than anything else in the back of the car to work. DC is a strange animal.

JC3

rear turn signals do not flash, they only go bright. like a blown front bulb. i replaced front bulbs twice just to make sure it was not the bulbs.
I already replaced the engine harness.
I just ordered a new front lighting harnes, maybe this will help.
I have been re-doing the grounds. I do have a wiring diagram, but really don't understand it. I am getting voltage from the ground on the battery.
I need to unhook ground or battery goes dead in 2 days.
Thanks, lots of good feedback from everyone, I'll keep trying.
We will be out of town for a week, so it's on hold right now.
Jim

scotts74birds

As far as the "no-flash" of the rear signals. In order for the bi-metallic strip in the flasher to work, enough current must flow through it to heat it up. I stand firm on a ground issue there.

blue 68 gts

Okay, makes alot more sense to me. I was trying to figure out a simple test check. It takes less then 30 seconds to test. It could also be a variety of issues going on as well.