Problem when alternator is engaged [Archive] - GrandAmGT.com Forum

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videoman
06-16-2009, 07:46 PM
Well to start off this thread, here's a bit of the story.
The other day I was installing a new mount for the battery located in the trunk and had a momment where there was a quick short. I blew 3 fuses (trunk rel. doorlock and radio) but after changing the fuses and starting the car I ran into another problem. the alternator must have blown too, cause when I ran the car for about 2 mins the alt was red hot. The Volt meter showed that it was generating normally, but I killed the ignition. I let the car cool down and installed my previous stock alternator. 15 mins later I verify everything is installed along with the alternator control line (connector that engages the alt.).

As I start the car There is a terrible screeching sound and I figured the belt must be slipping even though it seemed too loud for that. After about 10-15 seconds and a quick check I could find nothing wrong and turned the car off. The next day I took the two alternators in to be tested. The one I had installed first ( HO alt 160amp) registered as failed and seemed to seize durring the test. The second alternator ( original stock alt) tested fine and never showed any signs of failure even when the tester engaged the alt.

I get back home and reinstall the stock alt and get rid of the HO one. I verify everything is installed properly and connects the cable up. I goto start the car ( no SES or SVS lights or batt light) and the same thing happens as before the screeching sound. so I kill the car right away. I then wanted to test something, so I removed the control connector(3 wire connector) from the alternator and proceed to start the car. Running just off battery the car starts up with no sound. Everything runs fine, no screeching, no SES or SVS or Batt. lights.

Here's my question.

Where do you think the problem could be?

I am hoping it is not the PCM. The noise only occurs when the alternator is engaged and the current alt has been tested and verified.

Right now my mind is blank. I have gone through the fuses (didn't check them all) that I think apply. If anyone might have a clue or an idea, please post it up. TIA!

PS I have searched.