I have a 2000 Chevy Blazer 4WD and I'm having an issue with the alternator charging. The issue firstoccurreda couple weeks ago whenmy lights dimmed at night and I noticed that the voltage gage had dropped to the lower end and the battery light was lit up. After a few seconds the gage was reading normal again. While traveling down a gravel road the battery light seemed to come on and go off every time I hit a bump. A couple days ago, the voltage gage would change depending on the RPM of the engine. At a stop, the voltage gage would almost bottom out. Going down the highway, it was showing normal.

Yesterday, my Blazer started up fine with no signs of trouble. I stopped at a gas station and it wouldn't start. I got my Blazer jump started and started to loosen the positive battery cable to see if it was the alternator. The engine died before the cable was really loose. Jump started again and on the trip home, I lost all my instruments. Curious as to if this is actually an alternator problem or if there is a wire loose somewhere. Any help is greatly appreciated.

 

Check the battery and alternator cable connections and the battery terminal posts for corrosion looseness. Have both the battery and alternator tested.

 

I would run through your connections first before replacing anything.

 

You can't check these alts. like the 70's. You must have the battery hooked up you can have a brand new alt. and take the battery cable off while running and it will still die due to the computer....And you risk the chance of poping the diode in the alt. therefore costing you the money for the alt. anyways

 

I had the alternator checked and it failed. I appreciate everyone's help.