I have an LT1 in my 84 chevy pu that I just bought, I was driving the other day and it died, checked the gauges when I jumped it and the alternator is not charging. So I took it off and carried it to O'Reillys to have it checked and it passed on all the tests. I put it back on and still not charging, took it back off and to Autozone to check again, Passed again. Put it back on and still a no go. The only thing I can think of is that I was under the dash and might have knocked a wire loose (even though I don't see anything), but I had my friend look up the wiring and found that the remote wire (in the plug on back) goes to the ECM. The wiring harness has been built (due to late model engine and 84 body) so I only have 1 wire from the plug.

I was wondering if there is a wire under the dash that I could have knocked loose that would cause this or if the alternator could be checking out but since neither o'reilly or autozone tells the output that it is just so low that its not charging? And yes before anyone asks I have verified tightness of wires to battery and also checked wires on starter. Also if anyone knows which lead in the plug on the back of the alternator is the 1 that the brown wire from ECM goes into (there are 4 leads, 1 large and 3 small), we have been trying to see if that might be it and took the plug apart to test connection issues. Also, what turns the alternator on? +12v or resistance change, etc....

Any assistance would be greatly appreciated.

 

Noone with anything similar or anykind of input? Usually you guys know everything.

 

check for power to the wire in the plug, should be slightly less then battery voltage


also, do you have a battery/charging sys light on the dash?

if yes, does the bulb light up?