I have a 97 blazer 4.3 vin w. every time i use something like the turnsignal, my volts drop. i can watch my volt guage bounce to the rythem of my turnsignal. if i use my headlights, a/c, and other things at the same time, my volts drop.

i have replaced and added bigger ground cables, and put in a new battery. and it still happens. if i pull my positive battery cable off, it will continue to run. if i turn the headlights on with the cable off, my engine cuts off.

what could the problem be? maybe my alt. this problem has been going on for a while now, but i thought it was no big deal. now it is getting worse, and i need to get it fixed.

 

I would start by having your alternator tested.

 

Yep check the alternator, it seems to be working a little bit, enough to keep the engine running atleast, but it should also be charging the battery enough to run the accessories with out draining the system. Go to Advance Auto Parts, AutoZone, or Napa and they will run an alternator test for ya.

 

ha ha mine does this too and Im almost positive that its going to leave me stranded someday. The gauge moves even when I use the brakes sometimes. And sometimes it drops to 12 or so at stoplights :/

 

ok, i was hopeing for something cheaper, but that is my luck. i will pull it off this weekend and have it tested (not enough time now). i will let you know the results. are these alternators rebuildable? and if so, are they easy to rebuild? thank you for your help.

 

i changed my alternator today. i put on a new one, not reman or used. i still have the same problem. anybody have any ideas?

 

how long have you had all the extra mods in it???

 

I had the same issue with my 95, replaced alternator and still had the same problem. It turned out to be the charge back wire was bad.

 

In your mods, did you happen to put on an underdrive belt pulley?

This slows down the drive belt and frees up power, but it also spins the accessories slower. Mostly a good thing, but the alternator does not charge as well.

 

the problem was there before i started any upgrades. i dont have any underdrive pulleys.
what wire is the charge back. i have 3 wires on my alt.