Voltage light BUT good alternator and battery

[Slo2gen]

Just like the title says, I posted the other day about my voltage light being on so I took it to Advanced Autoparts and got them to check my battery and alternator. Both of them are good but the light still comes on sometimes and others it doesn't. The only other thing that I can think of is a short or bad ground. I did hook up my SAFC II and a boost gauge but all connections were solderd and taped excessively(sp?).

 

[larsenracing]

Did you have them test you alternator whale it was in the car all hooked up, If so that doesn't work to great also when checking your battery it works better to unhook it to test. Ive had them bad and there equipment not tell me that it was dying. To test the alternator you can get a voltmeter and test between the battery terminals and it should hold about 13.4V or so when the car is running if it fluctuates much or is lower than that you alternator is going bad and wont charge all the way. Good luck on your mystery.

 

[Sinclair159]

A good battery voltage will read around 12.6v anything under that i would be concerned about.. check your battery then go to your alternator... if your charging system is operating properly under load, it should never drop below .5v's over base voltage. then i would look at replacing your alternator.. make sure your battery terminals are clean, and all have good connections also... very important...

 

[Slo2gen]

Seemed to be the terminals so far, thing is that they didn't look bad? I will keep you informed if it still does it.

 

[Slo2gen]

Ok found it! My alternator belt was slipping, sometimes it would grab, sometimes it wouldn't. It was causing tremendous squeeling and voltage drop. I went outside to put a tensioner bolt in it and tighten it up but I am missing a bolt and nut at the top of the alternator. Now the belt dosen't even turn the alternator.