Amp gage jumping to discharge and back?

[750hp]

My car has just started doing this. Hopefully not to hijack the thread but to add to the discussion, would this be a gauge issue or an earth issue? It might do this for a couple minutes then the fluctuations stop.
While the gauge is fluctuating, the headlights also pulse...



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[patrickt]

Originally Posted by 750hp

My car has just started doing this. Hopefully not to hijack the thread but to add to the discussion, would this be a gauge issue or an earth issue? It might do this for a couple minutes then the fluctuations stop.
While the gauge is fluctuating, the headlights also pulse...

Well, that is not a "one time swing" with the current in-rush of the fan coming on (unless your fan is clicking on and off like a doorbell). What that is reminiscent of is a "chattering relay" type of activity. You know how you can wire a relay so that when it clicks on it disconnects itself, so it then clicks off, then it clicks back on, and then off, and it really almost acts like a buzzer? Anyway, what I would do is put an analog volt meter on your engine and confirm that the needle on that gauge is wiggling back and forth as well (and you can see that from under the hood). Assuming it does, and assuming you have an old-style mechanical voltage regulator, take the handle of your screwdriver and whack the voltage regulator and see if the needle wiggle stops for a second (or more). If that doesn't give you a clue, then the next step is to determine whether you have a variable load causing the needle twitch, or a variable charge rate causing the needle twitch.

[DanEC]

[quote=patrickt;1388260] take the handle of your screwdriver and whack the voltage regulator and see if the needle wiggle stops for a second (or more). QUOTE]

Sage advice from our electrical expert.