billsfirebird

iTrader: (1)

Ive got a pretty strange problem here guys and gals. I would appreciate any expert advice!

My headlights flicker and cut out when Im driving. It all started with a faint twitching while the car was in motion. Now it has progressed to the lights shutting off for a second or five! NOTHING else is affected as far as drivability. The engine doesn't show any signs of irregularity while the headlights dim. Along with the headlights shutting off the dashboard lights and radio cut out in unison. The turn signals still work even though the headlights shut off.

I notice that they will flicker during accelleration and even after pushing the clutch in to go to the next higher gear. I thought it might be in conjuction with speed, engine temp, or engine rev. Just when I think I have it pinned down it acts even weirder. I do notice a clicking sound either behind the passengers side dash or it may be in the engine compartment. DO I HAVE A BAD RELAY OR SOMETHING?

Here is what I have done so far. I have checked the grounds to the front headlights and cleaned them. Still flickering. I even replaced the dash board switch that activates the lights. Still flickering. Im at my wits end with all of this and any input or suggestions would be great.

Here is the details on the car. It is a 1984 Pontiac Firebird Sport Coupe. 2.5L 4cylinder, with a 5 speed manual transmission. I have no mechanical or performance upgrades on the vehicle, so I know that is not affecting the cars lights.

Well thanks for your time. Check out my site.
Bill's 1984 Firebird Restoration Projects email me @ billsfirebird@hotmail.com

Tim Burgess

Sounds like fusible link A is intermittant & needs to be replaced. It is one of the two fusible links connected to the large lug on the starter. Fusible links are available from most auto parts stores - Pep Boys has them.

mtccl

I had the same problem with my headlights flickering. Replaced my headlight modulator and alls well.

gettaway305

If some of your accesories flicker, then it is not a fusable link. I have had this same problem, only it happened when i was at a stand still.. It eventually fixed itself, but it is probably a grounding problem caused by vibration when your car is moving.

Tim Burgess

If you check the circuit diagram, which is attached in the following post, fusible link A powers the exterior (head, tail, marker) lights, and the 20 ampere accy fuse, which powers the radio, interior courtesy lights, hatch release, horn, etc. If the lights and radio are affected during the anomoly, then it is highly probable that the problem is associated with the fusible link A power feed from the large lug on the starter, which routes through the driver's side bulkhead connector as a large diameter red wire to the head light switch and the fuse block. Another fact worthy of noting is that the anomoly occurs when the engine load is changed, hence the engine moves in its mounts, causing the many wire harnesses connected between it and the chassis to flex as well. This also lends credibility to the probability of the fusible link, or the underhood power feed from that link causing the problem. If it were, in fact, a grounding problem, with both the exterior lights and radio affected, there would be many other systems affected as well, since the grounding points of both of those systems are no where near each other on the chassis.

Tim Burgess

The power distribution schematic is too big to attach, so here's the web site where it is located:
http://www.geocities.com/vtcamaro/Wire-Diagrams.html

billsfirebird

iTrader: (1)

HEY GUYS AND GALS!!!

Thanks go out to those who responded to my delima with my headlights flickering. Thank the Lord, the problem is solved!! I took all your advice in hand as I attempted to locate and fix the problem.

Turns out it wasn't a ground wire problem, it wasn't a relay problem, or a fusable link problem.

A power wire coming off of the positive terminal of the starter was defective. I could nudge the wire and sure enough the lights would flicker! I now have a better understanding of the wireing system of my car and I can see in the dark now!

Thanks again for your advise.

Tim Burgess

Glad you got it working - thank the Lord for all things, in deed! The wire at the large lug on the starter is actually the fusible link. It's a short length of a smaller gauge wire than the remaining length of the larger gauge power feed wire.

NOCANDO

I have the same problem with my lights flickering. It flickers as I drive. The battery gauge needle also moves to coincide with the flickering. I had this problem after installing an aftermarket alternator with an exterior regulator. Could I have the same problem????

Tim Burgess

It may be that the external regulator voltage reference input or regulator ground needs to be connected to a more stable point in the system - like at the large lug on the starter for the reference input.

MIG-29

mine does the same, i bought an overhaul kit from canadian tire, it worked perfect for abaut 3 weeks and now is doing it again, the volts indication do flicker at the same tempo. but seems that the system is going to overvoltage and cutting...again and again as a crazy circle.
how do i check if the volt regulator is ok?

Fernando.