Access the alternator, test the Red voltage supply wire, this should have battery voltage at all times.
Unplug the 3 pin connector, check pin 3, Orange and Light Blue wire, this should have battery voltage at all times from fuse 43 in the under hood fuse box.
Ensure battery cables are secured on power and ground side and there is no corrosion.
Leave the alternator unplugged, access the PCM located in the right front of the engine
compartment, unplug the PCM connector.
Voltage drop test the following circuits between the PCM and the alternator, ensure also the following circuits are not shorted to each other.
Yellow and Light Blue wire, pin 13 at PCM, pin 2 at the alternator.
Yellow wire, Pin 5 at PCM, pin 1 at the alternator.
If all the circuits to the alternator pass, and the circuits between the PCM and the alternator are good, suspect alternator. If the concern is still present, suspect failed PCM.
Hang on I will get pics
Edited by Tim West on 7/8/2010 at 9:43 PM EST