What causes an alternator to over charge? I had a junk yard alternator on my ZZ4 and one night coming home I noticed my lights were extreamly bright. I looked down at my volt guage and it was reading 18. Whoa! So that gave me an excuse to get a chrome alternator. Ordered a brand new one from a national parts supplier. Fast forward 8 months and I notice my electric fuel pump is getting louder and changing pitch. When ever the pitch changes the volt guage drops to 12. So I stopped by the parts store to have them check my alternator. They hooked up their little hand held computer to my battery. While my guage was reading 14 volts they said I was putting out 15.7. I have a painless wiring harness with auto meter guages. My father in law and I put it in, so I know the truck is wired correctly. What would cause two alternators to over charge in a years time?
Alternator overvoltage Sounds like a bad/loose connection in the voltage sense wiring or a bad/loose ground between the frame and the body. What alternator? 3 wire internal regulated? External regulated? Where did they put the meter leads to measure the output?
Also when you first put in the nator you turn every thing electrical on to set the regulator.Make sure all grounds and connections are good and tight. Cliff
