voltage problems??

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Apr 4, 2011
i have an 83 fj60 with a 2f i recently bought. it has 160000 miles it had been sitting for about 6 years when i got it it wasn't long before the alternator quit working i took it to a local rebuilding shop and had it rebuilt because apparently none of the auto parts stores could even get one. well i noticed my volts would be around 14 when i first started the truck and would stay about 14 for a few miles then it would go to 16 or higher sometimes. then one day i had it sitting running in the yard looking under the hood at another issue when i noticed the battery boiling over and swollen i checked my gauge and it was at 16+ i removed the battery which was old anyway and bought a new one thinking it was just the old worn out battery . i noticed it was still charging 14 when i started driving and going to 16 down the road a ways, if i turn on the a/c the volts stayed 16 until i push in the clutch they would drop back to 14 if i drove for 10 min without pushing in the clutch the breaker for the blower motor would kick. i looked under the hood after driving awhile and my brand new battery is starting to boil over. so i took off my alternator and took it back where it was rebuilt they took it in the back and tested it they said it was fine putting out 14.4 volts.i explained to them what had been going on and they said it sounded like a bad ground i went home put the alternator back on this time i hooked a 8 gauge wire to the bolt that holds the top of the alternator and connected it to the negative terminal on the battery . i started the truck and let it runs bout 10 min sitting still it stayed 14 volts so i started driving down the road and it went up to 16 volts and my headlights got brighter when i slowed down the lights dimmed and when i got home i sat with the motor running at idle it was 14 volts every time i accelerated the volts would go above 16 and go back down with the slowing of the motor ,interior lights and head lights were also going from dim to bright and back. if i cut on the turn signal the volt meter bounces up and down a little any thing else that could be wrong ? im thinking the voltage regulator is not working correctly once it gets warm and when they checked the alternator they didn't let the alternator get warm enough to start FU**N up. but im hoping there is something else causing the problem because im getting tired of taking my alternator on and off
Volt regulator .
The V.R. senses chassis voltage off a wire coming into the back of the alt through the ignition switch. If there is a break/weakness in that circuit (batt-fuse link-ign switch-harness), then the V reg will not see the V being produced by alternator and will raise the charging voltage, trying to get it to 13.8V.

Also, a bad ground between alt case and chassis will produce same result. Bad ground can be as simple as powder coat on the alt bracket.
thanx everyone for the info i ended up taking it back where it was rebuilt the whole truck this time they claimed my "ignition switch wires had got to close together over time they fixed it but then they crossed the leads up and blew the voltage regulator" i think this is bs i think it was the vr the whole time and they jus didnt want to admit they didnt let the alternator get warmed up when they checked it . this is the exact reason y i never let any one else work on my s***
Electrical-Testicle. I hate it when they don't work the way they should! ;)

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