95 Blazer A/C or Alternator problem

[Softwolf]

I purchased a 1995 Blazer LT, v6 Vortec 4.3L 'W' engine, 4wd, 145k miles, yada yada yada...that is quirky as hell due to the neglect of the previous owner. I've had it for about 2 months now. It has/had a load of problems, quite a few I've already taken care of with the help of searching the forum.

So far it's been reliable enough that I figured I'd take it on a short trip for the holiday weekend. Today's latest and greatest issue occurred as I was driving down the road at about 65 mph with the a/c running and the CD player cranking. I had already been traveling for about an hour when the alternator/battery light suddenly came on and the voltage gauge dropped from a steady 14 to the point where it was nearly in the red zone. I immediately shut the a/c and the stereo off (I didn't have any other accessories on) and about 10-15 seconds later, the alt. light went off and the voltage went back to normal. I turned around and went back home because I didn't want to wind up stranded somewhere. There were no more problems for the remainder of the ride, most likely because I kept the a/c off.

Does this sound more like the alternator is going bad or could it be something else (possibly with the a/c system)?? Any assistance would be greatly appreciated.

Cheers, Dawn

[MT-2500]

Alternators usually do not come and go.
Check your wiring power feeds and grounds and connections on alternator.
Also check and clean the battery cables.
Is the battery good shape?
Are you running one of the high amp boxes on radio?

[drdd]

On my 97, when the voltage gauge flickered intermitantly. It was the belt tensioner that had went bad. I don't know if you have one on a 95 though ...

Originally Posted by Softwolf

I purchased a 1995 Blazer LT, v6 Vortec 4.3L 'W' engine, 4wd, 145k miles, yada yada yada...that is quirky as hell due to the neglect of the previous owner. I've had it for about 2 months now. It has/had a load of problems, quite a few I've already taken care of with the help of searching the forum.

So far it's been reliable enough that I figured I'd take it on a short trip for the holiday weekend. Today's latest and greatest issue occurred as I was driving down the road at about 65 mph with the a/c running and the CD player cranking. I had already been traveling for about an hour when the alternator/battery light suddenly came on and the voltage gauge dropped from a steady 14 to the point where it was nearly in the red zone. I immediately shut the a/c and the stereo off (I didn't have any other accessories on) and about 10-15 seconds later, the alt. light went off and the voltage went back to normal. I turned around and went back home because I didn't want to wind up stranded somewhere. There were no more problems for the remainder of the ride, most likely because I kept the a/c off.

Does this sound more like the alternator is going bad or could it be something else (possibly with the a/c system)?? Any assistance would be greatly appreciated.

Cheers, Dawn

[534BC]

I'd bet on the alternator itself. Possible brushes.

[jbarsalou]

I'm having the same problem with my '97 Blazer. All of a sudden the voltage goes down and after a while it goes back up. I tried cleaning all power and ground connections at battery and alternator, new battery, and new alternator. I haven't fixed it yet, I only drive it around town. I assume it's a bad ground. Let us know how you make out.

[Softwolf]

After nearly 3 months of driving on borrowed time, the alternator finally completely quit on me as I was coming off of a circle about a mile from where I work. I could see the voltage dropping during the preceeding 10 miles...

I replaced the alt. with a rebuilt ACDelco and none of the voltage problems that I described in the first post have resurfaced.

BTW, dumb question, but what is the best way to budge the tensioner for the belt? I had a hell of a time getting it back on there with my bony girl arms and the longest adjustable wrench I have! I didn't have a pipe handy to make the wrench into more of a lever. I guess I should have thought about that before tearing the vehicle apart, but then I didn't think the tensioner would be such a beast either.

Now to fix all of the other billion problems with this vehicle.

Thanks for your help fellas!

Dawn

[MT-2500]

Thanks for posting back with how it went and the fix.
Glad you got it fixed.
They make a belt tensioner tool with a adjustable long handle that does help with the belt tensioner.
MT

[old_master]

If you ever have to do it again, remove the upper fan shroud, it makes the job a whole bunch easier, (7 bolts). A 6" 3/8 extension on a ratchet works great for moving the belt tensioner with one hand. Glad you got her going.