[DAVZ289]

Hey guys--

I replaced my alternator when I did my engine build-up, and now my alternator gauge is going crazy all the time. It doesn't really matter what kind of driving I'm doing, the gauge will rapidly go back and forth between D and C. At idle it slows down, but still moves. The only time it hasn't done this is one moment while I was driving it was stopped on C for just a few seconds, and then returned to bouncing crazily. I am almost certain that I wired the alternator right, as I consulted the shop manual, and it was pretty clearly labeled. The car starts fine, and all the electrical stuff seems to be working just fine, so I believe the alternator is functioning properly, but the gauge is going crazy. Any ideas on the cause of this?

Thanks
Dave

 

[Huskinhano]

sounds like an intermintent connection to me. Could be a loose connection, broken wire ect.. Check everything you touched, you'll find it.

 

[sharkmouth]

or a nutty regulator.....hell, I'd almost pay to see a mustang alt guage that actually moves!

 

[BillScott]

you could pull VR and alt and take them to AutoZone to test as a unit or get an analogue voltmeter ( not sampling digital one) and verify 13 V +/- 0.5 Vs at battery terms - if voltmeter fluctuates then it is not intermittent wiring.
also the connector on bottom of VR is just hanging there and may need reseated.