I have a 1996 4x4 4DR LT Blazer with a 4.3L and have experienced a strange electrical phenomenon (surprise surprise). Last night we got in it and no electrical power. There were no dome lights, brake lights, radio, no solenoid, nothing. So I checked the battery, at the battery cable screw heads, and found it to have 12.79 to 12.8 volts (perfectly fine); battery is 1.5 years old and is a top of the line including 3yr full replacement. We jumped it with my truck and it started right up. We then let it charge for a few minutes off of the alternator and decided to test drive it, backed it up 10 feet to leave and it dies completely again as soon as we stopped. Same no power to anything. Five minutes later we were able to start it just fine without jumping it. Drove it close to 20 miles at night and ran the vent blower to test for ability to produce current. Ran great no dimming pulled into our driveway. Next morning it starts just fine again.

The engine grounding cable contact at the engine was cleaned last summer and coated with battery contact sealer, looks clean and is tight. The battery has clean side posts and the associated battery cable ends are clean and free of corrosion. I looked up at the power lead going to the solenoid and it looks a little dusty, but no oil or anything. Wires look like all insulation is in place.

My question is what would cause everything to have no power including accessory lights (not even a dim glow) and then all of a sudden everything working fine. Can't be one of the in-line fuses (don't they always blow completely); can't be ignition because the dome (accessory lights) didn't even come on when opening the door; and now it has worked fine for a little over a days worth of in-town driving (32 more miles).

Would something shorting in the solenoid have anything to with it or is it some type of complete system short? Where could a short like that (wire that controls everything) possibly be? If it is a short I'm puzzled. Any help would be appreciated.

 

ignition switch

 

I had a similar problem a few years ago. I just cleaned the battery terminals and conectors and used some battery contact jell and it has been fine ever since. I also notcied that some battery terminals dont make good contact with the connectors on the blazer just because of there shape. You probably already checked these things but I figured I post this anyways just in case.

 

Mine did that once about a year ago and it never happened again.

 

mine did that and it was a bad battery, it was the original delco so i swapped it out and about a year later same problem. changed to interstate haven't had a problem since. guy at the parts store called it a battery internal short. my gauges were all going crazy at the same time.

 

I had the exact same problem and here is my 2 cents. Those side post screw in type battery posts are the problem. I agree with KyleS and I will take it further in that I did some research on those type of terminals and found that over time they corrode internally and fail to make a proper connection with the cable screws meaning they have to be fully seated in the bottom of the post/socket. Also another problem is they can be over tightened and stripped out or even broken off internally. So in short they look like they are making a good connection but are in fact not. Anyway I would clean the terminals and apply dielectric grease and go from there. If you see heavy corrosion inside the posts you can buy new ones from any parts store cheap. Good luck.

 

Also check the power going to the fuse box under the hood. GM's are notorious for having the connecting stud corrode internally and causing a "no power issue". This fuse box feeds the power to everything and is most likely the cause of your problems. Like stated above, the cables can corrode internally and look fine on the outside, again another GM/S-series issue.