LOW VOLTAGE PROBLEM

[Doug96CamaroRS]

Ok guys, although I aced circuit analysis, I have no clue what to do about this one. Let me give all of the details: I replaced my alternator about 2 years ago, and not too long after that, I began to experience a very inconsistent, nonfrequent voltage problem. Most of the time, it was fine (at about 14-16 volts I believe). Other times, it would drop to 8-10 volts. It had started becoming more and more frequent as time went on, and now it's constant. A few days ago, it had been on and off with the voltage drop 15 then 8, then back up and down again. All of a sudden, my check gauges light came on, and the voltage has been between 8 and 10 volts. I had advance auto do an electrical diagnostics test and everything checked out. So, does anyone have any ideas? My only thought is a loose wire somewhere, but I haven't noticed one...

[meissen]

Unfortunately I've got nothing to help, but I wouldn't trust Autozone or O'Reilly or any of them. I had my alternator tested at least 5 times while I was having problems and everyone said "Nope, checks out OK." Until I was driving to work and the "Check Gauges" light came on. Replaced the alternator and hey wouldn't you know, problem fixed.

[98blackbeauty]

Could be loose or bad ground connection. Measure voltage at battery terminals then from ground to alternator terminal they should be the same. 13.5 volts engine not running. Batterys can short out intermitantly, diodes in regulator (internal in alternator) can short intermitantly. Measure from + terminal of bat. to various grds, ie; engine block, body parts, all should be the same.

[2002Z4CSS]

Sounds like the voltage regulator in the alternator is going bad or like Larry said a bad connection.

[Doug96CamaroRS]

So my best bet is to replace the alternator?

[Doug96CamaroRS]

Car didnt start this morning... I'm guessing the alternator?

[TB2]

The only way to properly check an alternator is OFF of the vehicle on a test stand. Also check grounds as stated. Especially body grounds.

[2002Z4CSS]

Car didnt start this morning... I'm guessing the alternator?

Make sure there is no draw on the system when the key is off and after the modules go to sleep. The charging system can be tested with the engine running with a tester like a Sun Vat 40.

[Doug96CamaroRS]

Got it running. The wire that goes into a one-wire harness that plugs into the alternator was broken. lol

[2002Z4CSS]

Got it running. The wire that goes into a one-wire harness that plugs into the alternator was broken. lol

Glad to hear you fixed it.

[HighVoltage]

if this was my car i would put a volt meter on the battery with the car running and check it. Do this under load (A/C, Wipers, high beams, ect). if its not right i would change just the regulator and see if it corrects the problem

[Gaspo]

Got it running. The wire that goes into a one-wire harness that plugs into the alternator was broken. lol

That was going to be my first suggestions. Happened on my trans am.