Voltmeter going haywire, could it be faulty?


Founding Member
Mar 13, 2001
Lung Gyland, NY
I will be driving along and my (stock) voltmeter will just all of the sudden jump down to like 10. As a result the battery idiot light comes on. Tnen it will jump back up to ormal after a minute or two. The battery shows no signs otherwise of going. Could this just be a faulty volt gauge? Does this happen at all ever? I have a 92' with 120,000 mi. Thanks
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If the battery light is coming on, then its not your gauge in the intrument cluster.
Always start from what you recently replaced first.
Check the conections on the new (rebuilt) Alt. Just because its new doesn't mean you got a good new part.
Good luck.
i agree with 10 hole. it could well be a loose connection, hence the intermittance.

i would normally say get it tested, but with it being intermittant, it could be tough to find with testing (unless it does it while testing).
is it a stock amp alternator?

good luck.
Yeah, it is the stock amp alt. About a year back I had a small fire.....the protective coating of the wires going to the alternator rubbed off and touched eachother. I had that fixed......they spliced in new wires and put in a new rebuilt alternator. Then a couple of months ago, that piece of junk rebuilt started sounding like it was full of rocks so I had that replaced. Now I have this problem. I swear, my Mustang has been nothing but a great, reliable car for me now for 6 years, but it just seems like I have a damn alternator problem like every year!