94 tbird volt gauge surging

I cant figure this one out! while you are driving you will hear a loud click and the volt gauge will drop all the way down for a second then return to normal, it will actually dim the headlights at night. Thought it was the ac compressor drawing for the climate control but does it when you have that shut off. had charging system checked and that checked out fine. Also considered a voltage regulator, but cannot find one. Anyone have any ideas what could cause this? 3.8 liter :banghead:

similar/same problem w/'96---don't hear the click noise but volt gauge will bounce back & forth, occasionally surging to the extreme & my lights flicker, gauge surges start/stop randomly; changed battery (seem to have extreme corrosion problem), still have problem, i could use help to.....

Welcome to the forum. The voltage regulator is inside the alternator. I would suggest you check and clean all battery and alternator connections. This would include the ground connections to the engine and body.

I did not have any corrosion problems, but had already brushed off the connections at the battery and the grounding cables. Something else I did to troubleshoot was to take the serpentine belt off and run it. It does it when the belt is off the alternator and a/c compressor also. Any other ideas

It sounds like there is a high load relay closing somewhere. When it closes there is a large surge of current to whatever the load is. See if you can find where the clicking sound is coming from. Does it happen radomly or under certain conditions? Another thing to try is removing fuses one at a time to try to narrow down what circuit is being affected. If you use a clamp on ammeter on the battery cable you can see how much current is being drawn. You can probably get one of these at AutoZone for free-once you return it they will give your deposit back. Once you know how much current is being drawn you can start removing the fuses that have a higher current rating then what is being drawn. This will narrow down how many fuses and circuit breakers you will have to remove.

It seems to do it after you start it and drive maybe 1 block, then after that it seems to do it every once in awhile. It would prety much be impossible to locate the specific source of the click, it is under the hood and will not do it unless you are driving down the road. I dont recall it ever doing it when you are just sitting in park. The sound reminds me of the a/c clutch kicking in

Then disconnect the connection at the A/C clutch and see if you still hear the clicking.

already tried disconnecting the ac. Went out and picked up a new alternator yesterday hoping it was the voltage regulator, but it wasnt! Sounds like it is coming from the driver side front fender area. I spotted 2 relays in the fuse box sitting there. I am going to pull the relays out of my 95 and see if it still does it

Some auto supply places sell stethascopes to listen for engine noises. See is you can find one and replace the hose with a piece long enough to go from the relays to where you sit. You might be able to snake the hose through a hole in the firewall. Tape the probe end to the relay and then listen to see if the relay closing causes the problem. Move the probe to other relays and listen to them also. You do realize that it is normal for the regulator to take a second or so to catch up to the current surge so there could be a moment when the lights dim but not drastically.

took notice that my 95 does the same thing, it just isnt as noticeable or as loud as on the 6 cyl. It doesnt seem to effect anything other than driving me nuts, so I'll just let it go for now