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Flickering lights dilemma

6

67390GT

New Member
Now that the tach dilemma has been taken care of, it's time to move on to the flickering lights dilemma.
All the lights on my 67 flicker while the car is running: dash lights head and taillights, warning lights, courtesy lights everything. I replaced the alt, volt regulator, even the light switch. Took the fuse panel out and cleaned all the connections(there was some corrosion). all to no avail. It has benn going on for quite a while now, and I don't recall doing anything that would cause it. Alt grounded to engine block, engine block grounded to firewall, dash cluster grounded to firewall, regulator grounded to fan support all look clean and good. I disconnected the neg battery cable put a test lamp between neg terminal and neg cable nothing. Put a voltmeter from neg cable to neg post got a reading of 2.5 volts which steadily declined until it reached .45 volts and held there. Is this normal? What else should I look at?
 
Examine closely the positive and negative battery cables for corrosion. Also, the VR needs to have a good ground, which is the chassis to the fender apron. I always scratch some paint off on the one corner where the grounding lug goes.
 
Like you, Mid, I always sand the area before securing a ground. Absolutely no corrosion on cables, however, I do recall that once upon a time the neg cable did hit the cooling fan(maybe it was the other way around) and some insulation was stripped off, maybe a few strands of wire were cut. I wrapped the affected area with electrical tape and figured that was good enough. Reasoning ?: its only a ground, shouldn't matter. And quickly forgot about it. You think that could be a cause?
 
Is there any fluctuation of voltage anywhere in the system? I would trace back thru the light system wiring and look for voltage oddities that would effect all the systems. If there is a voltage fluctuation, is it present in any system not related to the lights. It could be an entire electrical system issue, just not noticeable except in the lights.

I doubt a couple broken strands on the ground you described would hurt much....but it could be a start for some corrosion.
 
I agree. Its most likely not a lights only problem.
if the car is running with all lights off, doors closed all acc
off. The brake warning light still pulsates.
may be a stupid question, but why doesnt this happen with
ignition on, but car not running?
Do you think the puddle of electrons on my garage floor could be a clue?
 
Why is a brake warning light on when the car is idling?
 
I knew somebody would catch that;broke a brake line, fixed it, but piston in distribution block is stuck.Gonna have to take the distrib block off, but I can barely get one hand down there. Clutch linkage and power brake booster take up a lot of room and it is a 390.
Im kinda hopin that will fix itself.
 
I would start at the battery then move to a headlight wire, or other item that is easy to access and get a meter on the wires. Even the fuse box, before and after the regulator, just mainly looking to see where the fluctuation happens at.
 
Sounds like your using the old style reg, If so remove the cover and lightly file the point contact inside and retest.
If its a new solid state unit, replace it.
 
"Mach1Rider" said:
Sounds like your using the old style reg, If so remove the cover and lightly file the point contact inside and retest.
If its a new solid state unit, replace it.
Click to expand...

I was thinking regulator as well
 
I had the old style mechanical regulator, but replaced it with a electronic one hoping that was the problem, but of course it wasn't. I'll try to get out there today and do some dvm probing see if anything is amiss.
 
Finally got around to looking at the wiring (been in the mid 90's - no a/c in the garage)and discovered some of the OPs work on the wiring around the start solenoid that was questionable, including a big 'ol scotchlok!! Fixed them all and now the lights only pulsate at idle. Too low? I think I can live with that, got another wire that needs attention - manana. Thanks for everyones input.
 
Lights pulsing at idle is fairly normal, as the alternator is not putting out enough juice. You'd think, though, that the battery would regulate the voltage to the car.
 
Battery voltage stays constant while idling so I guess I will just live with it. Isnt it amazing what some people do to
these cars. Scotchloks? what could be worse and I had a couple of them on the back of the instrument cluster. Why? What could they possibly be for? Ripped them out, but now I have splices....Got splices everywhere.....what did this guy do? Run another car off of this ones wiring?
 
I had one Mustang that came to me with wire nuts on major ignition connections behind the dash and a few under the hood on the ignition stuffed into a frame hole....so nice......

A higher idle may help the pulsing but you still want it to be at the correct idle speed. As said....kinda normal for older cars.
 
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