[KVman389]

Have a 66 gto, pretty much stock with HEI ignition. Recently, whenever I turn on my turn signals, the headlights, dash lights blink in unison with them. When the brakes are applied, everything dims. Voltmeter fluctuates in unison with the flashers, and drops 1.5-2 volts, also drops when brakes are applied, but recovers almost instantly. Have checked all grounds, (I think). Battery, alt., starter, and regulator check out ok. All visible wiring appears good. Please help,only option I can think of is a full trace of the charging system. Thanks.


Bert



i

[KVman389]

Have a 66 gto, pretty much stock with HEI ignition. Recently, whenever I turn on my turn signals, the headlights, dash lights blink in unison with them. When the brakes are applied, everything dims. Voltmeter fluctuates in unison with the flashers, and drops 1.5-2 volts, also drops when brakes are applied, but recovers almost instantly. Have checked all grounds, (I think). Battery, alt., starter, and regulator check out ok. All visible wiring appears good. Please help,only option I can think of is a full trace of the charging system. Thanks.


Bert



i

[PMDRACER]

Geez.... This is gonna be a long one to find.

Does it happen only with the engine running? If so, it's something in the charging system.

Otherwise, disconnect stuff (or pull all the fuses) until you find the culprit.

I had a tach that did this to my wife's car. It had a bad internal ground.

TIGER EFI - Electronic Fuel Injection for the Traditional Pontiac Engine. [email protected]

[george kujanski]

Sounds like either you have a poor regulator case ground or your alternator can't supply the necessary current under these loads, meaning your belt may be loose, or you are not getting enough output from the alternator. Possibly an open diode in the alt? Check to make sure you have battery voltage on regulator terminal 3 (battery sense).

Regards, George

[PITTSBURGH 64]

I would disconnect all the dual filiment bulbs on the car sounds like the break-turn signal circuit is backfeeding to the lighting circuit. Does it do it when the head lights are on, do the break lights come on with the headlights?

[sleepy]

Sounds like a bag ground. Check the ground on the tail lights. I'll bet you find a bad connection or wire.

[sleepy]

Also look fot power wires rubbed through and grounding to the body.

[KVman389]

well let's see, yes, it only happens when the engine is running; no the brake lights don't come on when lights are turned on. New alt. belt, torqued to 75lbs. Will check the tail circuit next, then check signal and brake switches. Yes it also happens with headlights on. Thanks for all the new ideas, will make for a full day. will let you know if I find the specific problem. Again, thank you.

Bert

[Bob with the 66]

I would check the turn signal wiring going into the steering column. It sounds like a wire is grounding out. I would loosen the bracket holding the bottom of your column and jiggle the wire harness by the metal cover and see if is the problem. If your dimming problem happen's only when the turn signals are "on" this harness is what I would check first.
Good luck, wiring is a pain.

[nickg]

try pulling the instrument panel fuse first to try to isolate circuit sounds like a bad ground or bad turn signal sockets are notorius for that also if you recently to the instrument panel apart you may have check to make sure all the screws are in & the circuit bord isn't folded over or otherwise damaged.

[KVman389]

thanks for all the great info. Took a while to get to everything. Finally got down to the starter and solenoid, found a bare section on the ground, and the field strap was missing the screw.Replaced ground, secured the field strap, Problem stopped, and has not reappeared. This might help someone else who runs across this problem. Again, I thank all of you for your information and advice, I did find a couple of potential future problems while going through all of the checks. Bert