Have a 79 elco with 2004 5.3 Vortec. I have already replaced one alternator, and rewired to what I THOUGHT migh be correct. However, battery needs charging consistantly, and car dies immediately if positive is disconnected.

Trying not to have to do this again, I have a come to the trusted experts once again. Back of alternator wired to starter. On the plug top HOT wire to battery (S on alternator), and taped wire (I on alternator) hides a 470 Ohm 1/2 watt resistor wired to idiot light. L and P on alternator inactive. Although I have looked at numerous diagrams, have I wired incorrectly? And If so and I fix it, will alternator work or have I shot this one too? Same thing...will I need to replace resistor?

Thanks in advance for any help.

 

If you have the idiot light then you don't need the resistor. Also sounds like you have that hooked to the wrong lug. See below

Last bit of advice is to take the alternator to a parts store and have them do a free check. Eliminate that as a possibility.

 

Thanks...I just bought the alternator new, although I know nowadays that doesnt mean much. Would the resistor adversely affect proper operation if its not needed?

 

Yes, having both might be an issue.

Recheck my last post. I just edited it. The idiot light goes to the L lug

 

Ok, cool. Alternator checks fine per parts store, moved connection to "L", but doesnt seem to charge with or without resistor, and idiot light does not come on when key is in "on" position with car off. Im starting to think maybe this circuit is no good (imagine that on an elco) so should i just try and find an "key on" hot wire?

 

got it done...went to wiper circuit...thanks for all the help!