Put in a new atl wont charge
If both the alternator and the battery are good, either the alternator isn't turning fast enough (slipping belt or engine idle speed too slow), or you have a wiring problem.
To check your wiring, look for the "1" terminal on the back of the alternator (left side of spade terminal connector). When you turn the ignition key to the run position without starting the engine, the alternator warning light should be at full brightness. If the bulb is burned out, the alternator will not get the excitation current it needs to start up (it goes through the bulb). With the engine running, you should measure 12 Volts at the 1 terminal (this is the excitation terminal).
Another thing to check is whether the battery charge wire is good. If it is corroded inside at the battery clamp end or burned out, you won't get charging even though the alternator appears to be working. If you don't have an ohmmeter, you can make a quick test by adding a new 8 AWG wire between the output terminal and the battery clamp. If the battery now charges, the original wire is bad. If this works, I recommend installing an inline fuse at the alternator end no larger than the largest size used in your electrical system, just in case something happens to the jumper wire. That way you won't burn out your alternator.
The heater/AC issue could very likely be a separate problem, but inadequate power may keep that system from running properly. (Note: low idle speed or belt problems will also be detrimental to AC performance.)
Jul 10, 2011 |
1989 Chevrolet Corvette