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Electrical

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Electrical
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Location
Tampa, Florida
Vehicle(s)
1979 CJ5
Good morning all !!

Need a little guidance... My 79 CJ5 recently developed an electrical issue that I can’t figure out. One day driving home last week my voltage gauge went down to 0 while I was driving home so before I got stuck somewhere and out of caution I pulled over and got towed home. The next day I pulled my alternator and battery to have them checked and they were both fine. After a couple of hours looking for something loose and checking ground wires out of frustration I bought a new alternator. Now my volt gauge is telling me that it’s over charging. I noticed last night when I was driving around that when I have my turn signal on the needle on the gauge ticks back and forth and when I raise the rpms my headlights get brighter. Both of theses quirks never happened before this situation. Electrical issues have never been my thing so I really need some help, hopefully someone can lead me in a direction.

Thanks a million
 
What does your voltage gauge show?
Anything under 15v is good.
Also-Run a wire from your dash panel to the NEG(-)battery post.
When you had that altenator ck'd. What did it show for voltage and amperage output?
How old is the battery?
LG
 
Showing 17v

They didn’t tell me what the volts or amps were. They just told me it was okay and after getting stumble is when I bought a new one.

The battery is about two years old.

Being the gauge has never twitched before I never thought about running a wire from the dash panel to the neg post.
 
I would suggest checking the wiring. A bad ground circut can be checked by running a jumper wire from the alternator housing to the battery negative. Check the dash panel like Lumpy suggested. After all these years the two fusible links tied into the starter relay could be bad, jiggling them while the engine is running and watching the voltmeter could check that. Make sure the battery and alternator cables are in good condition.
 
I would first confirm the reading is correct, with a volt/ohm meter.
What does it drop to when you turn the headlights on?
LG
 
My wiring harness is only about 4 years old. When I started his labor of love in 2011replacing the harness was on the top of my list. So I bought one from painless for about $600 and I had a coworker that thrived on doing things like that and he was always my go to guy when I was rebuilding. Unfortunately he moved and we lost touch. I just purchased a multi meter and I am in the process of reading how to test it correctly. I will let you know what the voltage drops to as soon as I figure out how.
 
Hook the meter to the bat and compare the reading with what the gauge says. If the gauge is working right it should read the same
 
Okay.... when I’m sitting idle the meter bounces from14.8 to 15.5. When I raise the idle it goes up to 16.6v. It never went higher than 16.6 and I kept the rpms up. Which means I didn’t just spike the motor I brought up the rpms and kept it there for about 45 seconds.
 
I could just run around with everything on (Fog lights, head lights, radio and fan) When I had everything on I was still sitting between 13.8 to 14 v. Better than 16 I guess😂😂 LMAO. Might irritate a few people though!!
 
It sounds like a bad voltage regulator to me.
 
Just to give you guys an update. Just because you buy something new doesn’t mean it’s good. I took the alternator back off went to the auto parts store and had them test the alternator and it tested bad. Got a new alternator put it in everything is working good. Drove myself crazy for three days trying to figure out something that wasn’t there. Thanks for all the help guys it was worth it and a great learning experience.
 
I never buy a altenator or starter, without the store testing it before I leave.
Stopped play'n that run-a-round game many years ago
What's your voltage reading now?
LG
 
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