sounds like a bad ground. a lot of the g.m. trucks have a poor ground set up.
good luck !
did you check your battery and alternator?
is your battery Low or poor?? Charge your battery on slow charge for 8hrs to give it a good deep charge, Installing an alternator on a low or dead battery will ruin it and also not charge your battery properly.. An alternator is not a battery charger its a battery maintainer!!
The alternator only needs to be replaced when it fails. Its not a part that needs to be changed during routine maintenance. If it ain't broke, don't fix it!
An alternator from a 2000 Chevy blazer will fit a 2002 S10 blazer with a little fabrication.
You have a problem with the charging system, probably a bad alternator.
generally that you have an electrical issue, either your battery is dead or dying, or it could be your alternator also... make sure you have booster cables in your vehicle
take off the belt unplug the wire connector form the back of alternator take the nut off the back of the alternator that holds the wire that is connected to the positive battery terminal and take the two bolts on the bottom of alternator that holds it to the engine
If a 1991 Chevrolet S10 Blazer warning brake light always stays on, it could just be a malfunction of the light. To reset it, disconnect the battery for 10 minutes.
1st remove negative battery cable from battery. then remove electrical connectors from alternator with ratchet, rotate tentioner pully to remove belt. (near top/center of belt) remove support bracket and mounting bolts and it's off.
Fuel trim malfunction, bank 1.
Pull the hot (+) positive lead on the battery while running...If car quits it's bad. Best way is to put voltmeter (Multimeter) on battery while running..if 13 + volts at idle then alternator is good, if 14+ then it's great!
ALTINATOR OR STARTER. JUMP START CAR, TAKE POSITIVE CABLE OFF BATTERY,IF CAR DIES IT IS ALTERNATOR. GOOD LUCK