Another Electrical Problem!!!!!!

[Mosesatm]

Don’t know if we’ve talked about this problem but I don’t think so, and it’s an interesting one.

All my lights work great with the key off, and with it turned to the left, and with it turned to the right, but when I start the engine I lose rear lights. All the front lights work fine but the taillights, stop lights, and rear turn signals don’t cooperate. The only rear light that works with the engine running is the license plate light.

My first thought is that there is something wrong with the headlight switch but why would it only act up with the engine running?

Any thoughts?

 

[roadbum]

This may sound kind of naive but try moving the key after the car is started. Had a 60 caddy that did that to me in the middle of nowhere New Mexico more years ago than I want to remember. Had to put pressure against the key to get lights.

 

[Mosesatm]

Hmmmm. There's an idea.

My old GT/CS would die for no apparent reason. I'd pull over to the side of the road, start the car, and go a few more miles. Then it would die again. Drove me batty.

By pure luck I found out that the connector that plugs into the ignition switch was loose. After enough bumps it would lose the connection. Turning the key must have put pressure on the switch and made just enough of a connection to start the car.

 

[rvrtrash]

I would take a look at your ground wire on the framework over the gas tank fill tube to make sure it's a good connection. If the front lights are working, that would imply that the power source side is ok. It may be that the vibration from your engine is breaking the ground side connection in the rear. The license plate light grounds out through its mount to the body so would be unaffected by a loose ground for the tail lights, etc. Just guessing here, but hoping I'm right and it's really that simple.

Steve

 

[Mosesatm]

hoping I'm right and it's really that simple.

Steve

So am I Steve. Thanks for the educated guess.

I'll run out to the garage right now and check that ground and the ignition switch.

 

[Mosesatm]

I poked around at all the trunk wiring and a the back of the ignition switch, started the car, turned on the lights and everything worked; then it didn't work; then one taillight bulb lit; then it went out.

Since I played around with both the trunk wiring and the ignition switch I don't know which one fixed things but I'm leaning towards the switch, just because it seems to be a little loose in the dash. But only 1 light working would seem to point to the trunk wiring. I'll go through our usual routine of checking all the bulb sockets and grounds and see if any obvious pops up.

Too late tonight to work on it so that will be tomorrow nights project. Hey, I'll get to use my new volt meter!!!

 

[Mosesatm]

All the driver's side tail light sockets were loose. I have no idea what that had to do with the lights not working when the car was running but I tightened them and everything seems to be working fine now.

Looks like the next weekend project will be completely refurbishing the tail lights. I need a new bumper anyway so everything falls into place.

 

[rvrtrash]

Glad you found the problem. I was getting ready to ask how it was coming. The sockets being loose was basically the same as the ground wire being loose and vibrating. The lights ground through the socket body to the tail light housing. There is a ground wire that screws to the housing and the other end of that wire is what mounts to the frame over the fill tube. Same circuit path, just further upstream, and harder to fix, so I always have a look at the easiest spot first. Feel free to email if you need help.

Steve

PS. Have you considered just bringing it up next summer so we can go through the whole system and then spend the weekend white water rafting?:grin:

 

[Mosesatm]

PS. Have you considered just bringing it up next summer so we can go through the whole system and then spend the weekend white water rafting?:grin:

My wife is on an adventure kick so I might be able to talk her into that.

Why is it that when men go off the deep end in their 40s it's a "midlife crisis" but when women do it they're "finding themselves"?

 

[Mustanglvr]

It comes from the movie "Kramer vs Kramer" where the wife claims that all her life she has either been someones daughter, someones wife or someones mother and had never been able to be herself and do for herself, so, she needs to "find herself".

 

[rvrtrash]

She needs to "find herself" on the Salmon River at the end of June sipping a cold one and catching some rays!:grin: When the water is at the right level, I've been known to have 2/3rds of a 16 ft. raft in the air going through a roller coaster wave. We can provide adventure. Cory, you out there? Going to join us this year?

Steve

 

[Mosesatm]

An update on the taillight problem.

Turns out I hadn't fixed the problem.

Since the lights were dead when the engine was running I figured it must be an alternator or solenoid issue; maybe the alternator is putting out too much juice and tripping the breaker in the headlight switch. But why would the license plate light work?

Took off the alternator belt and started the car. No problems with the lights at all. Turned off the car, put the belt back on, and started it. No lights. Hmmmmm.

Then it hit me. Those super duper LED lights have all sorts of chips, and resistors, and diodes, and whatnot on them. They must be getting too much voltage or current and shutting themselves down. That's why the license plate light works when the taillights don't.

Sure enough I put the 1157s back in and everything works great!!!!

I still don't know why the LEDs won't work but I'm hoping an e-mail to the Mustang Project people may answer that question.

The mechanic who recently did all the work on my car said he'd put in both headlight and taillight relays for me for a total of $50. Can't argue with that!

 

[rvrtrash]

And all this time I thought we were working on bulbs, not LED's.

Steve

 

[68gt390]

Arlie;
When you get an answer from Mustang Project please post it. I'm running the same LED lights in the back but, have had no problems. When I swapped out the lights last year I also swapped out the alternator with a new one.

Don