wally3b4

My battery light has recently been coming on intermittently and is on more than it is off now. With the van running and the battery light on, the voltage at the battery and the output post of the alternator is right around 11.6. With the van not running, the voltage is right around 12.4. I haven’t been able to catch it with the battery light off. I installed a new battery with the same results. I pulled the alternator and had it tested and was told it is functioning properly. I re-installed it, the battery light stayed off, and drove for about a week with no problems. Then the light started coming on again. I checked the voltage at the connector on the alternator of the ORANGE feedback wire and it tested out at 11.6 with the van running and around 12.4 with the van off. I am wondering if anyone can tell me what voltage (if any) I should be seeing at the RED wire coming coming from the connector on the alternator which feeds the PCM (?) module. Thanks.<!--?xml:namespace prefix = o ns = "urn:schemas-microsoft-com

EinST

The RED wire is terminal L output to the PCM so that it can sense when the alternator is or isn't putting out enough voltage to charge the battery. If the alternator tested good on the bench, I'd think there's something going on with the battery cables. The alternator is grounded through its housing and thus measure the resistance between the housing and battery negative terminal?

wally3b4

EinST, thanks for the reply.

I tried following all the cables and wires to and from the alternator and battery. I checked terminations wherever I could and metered on both sides of the fuse for the ORANGE wire. As far as I could tell, there was no voltage present on the RED wire going to the PCM module. In the end, I pulled the alternator again (did not want to do that because it was a huge pain to remove and took forever) and had it tested again. This time it failed. I bought a reman and installed it and no more battery light. The only thing I can think of, is that when I pulled it the first time, all of the bumping, banging, and jostling re-seated the brushes just enough to pass the bench test and run fine for a week. On the bright side, it only took me about 2 hrs to remove and replace it the 2nd time...

EinST

Glad to hear. Hope that's all there's to it. Thanks for the update.