Electrical problem
1988 Chevy Blazer V8 Four Wheel Drive Automatic 68000 miles

My Blazer won't start. When I turn the key, the battery gauge dives all the way down and the engine turns over just a few degrees, but doesn't continue to rotate. I've had the battery charged and tested. They said it was ok. I've had the starter tested, they said it was ok. I jumped the terminals on the starter and got the same outcome. I have 12 volts at the main power wire on the starter and a test light dimly lights up on the signal wire to starter. What do I check next? What's not working the way it should?

Hi:
When you had the battery tested, was it load tested? It sounds like there may be 12 volts at the battery but when there is a load on it, it shorts out internally. Also, make sure the battery terminals are clean and tight and the ground on the engine block is clean, tight, and there are no breaks in the cable from corrosion.

Let me know.

Joe

The truck does the same thing when I try to jump start it. They should exclude the battery from being the problem, right?

The ground I'm checking should go from the battery to the engine block, right?

What tests can I do with my multimeter to verify the condition of the power wire to the starter? Continuity and proper voltage? Anything else?

You can't exclude the battery unless it passed a load test. It could read 12+ volts then die under a load.

As far as the ground, yes the one to the engine block and any you find on the body.

As far as the multimeter, I need you to check voltage. There should be two wires at the starter, a large one and a small one. The large one will have 12 volts, but the small one should only get 12 volts when the key is in the start position.

Let me know how it goes.

Joe

My battery tester says that the battery is ok. It tested it at 850 cca and it read 570 cca. It said it needs to be charged, but it's ok.

I checked the grounds that I could find and don't see any thing wrong.

I'll check the starter wires tomorrow when I have a helper.

Hi again:
When you tested the battery, did you use a specific gravity tester or an actual load tester? Let me know what you find with the starter.

Joe

Just a load tester. No specific gravity.


I put a multimeter on the signal wire to the starter and I think i only saw 3 volts when I turned the key.

Hi:
If thats all your getting, either the cable is bad, you have a bad ground, a bad starter relay, or the ignition switch is bad. I would start with the easiest. If you check under the hood in the power distribution center, see if there is an exact match for the starter relay and switch it to see if that helps.

Joe

The weather was nice today, so I got out there and found out there's a bad ground somewhere. I put a jumper cable from a starter bolt to the neg. terminal on the battery and it turned right over.

I then cleaned the connections on the neg. terminal and the ground cables to the block and the body. I checked those ground cables for continuity and didn't see any trouble. But it still won't start without the jumper cable. Is there another ground cable that I should look for or inspect?

Thanks so much for your help with this!

Hi:
If you need to ground from the battery to the starter for it to start, you may just want to run a new seperate ground to the starter. There must be corrosion where the starter bolts and you're not getting the ground you need. Either remove the startrer, clean mounting surface, and replace starter to see if that works, or just bolt a new ground to one of the mounting boltes. Make sure the wire you use is as heavy as the one going to the battery.

Joe