Complete loss of 12V power......

[ericinga]

88 C1500 5.7L 144K miles. I've only owned the truck a few weeks. It has been driven daily for the last two weeks.

Yesterday, took my son the park. The truck was parked for an hour or so. Returned to start it and there was no power. Nothing worked. There was no response from turning the key.

Another person gave me a jump start and took the truck home. Entire trip the gauge read 14 volts. At home, tested the battery with a DMM and it was at 12.1 volts. Truck started right up. Alternator is putting out 14.3 volts. Threw the battery on trickle charge over night. Truck started up and ran fine on the morning commute.

Does this sound like an intermittent voltage regulator failure? Is there a relay in the 12V system that could fail intermittently and cause a complete voltage loss?

Plan to trace the 12V power and ground wires tonight.

TIA

Eric

 

[Oldblue98]

Did you check the battery after the charge on a load test ? Check terminals for corrosion at all points. Grounds !? Check terminals at alternator to see if they look loose, worn, burnt . Standing volts does not mean the battery is good.

 

[ram1220]

Check the negative battery cable connection at the battery. My 90 is always coming loose It's the curse of the side post battery. Corrosion will also cause an intermittent problem.

 

[thunderstruck]

I agree with checking for corrosion at the battery terminals. If your truck still uses the side posts, You won't see how bad it is until you take those connections apart.

 

[Elroy]

your wiring is corroding inside of the insulation, i replaced the cable that goes from the batt+ to the fuse block going over the radiator ( on my 96 2500), i tried putting a new end on it first, but no matter how far back i cut and stripped it the wire is green and spilling powder, if you see any heat deforming of the insulation near the terminal its bad, solution is to replace all cables from battery to fusebox/ alternator and grounds , someone recomended adding a ground cable from alternator body to batt neg, i will do that soon

 

[sewlow]

your wiring is corroding inside of the insulation, i replaced the cable that goes from the batt+ to the fuse block going over the radiator ( on my 96 2500), i tried putting a new end on it first, but no matter how far back i cut and stripped it the wire is green and spilling powder, if you see any heat deforming of the insulation near the terminal its bad, solution is to replace all cables from battery to fusebox/ alternator and grounds , someone recomended adding a ground cable from alternator body to batt neg, i will do that soon

YES!!!
It's called 'The Big 3'.
IIRC, there's a 'how-to' thread on here somewhere.
A member or 2 sells pre-made kits, too.

 

[Eveready]

All of the above and make sure and check the main terminal on the starter. That is a big point of corrosion. A drill with a wire brush will likely get you a long way toward the fix. Remember that a new battery will possibly mask the problem but it WILL return if any of those wires or connections are bad. Please be sure and post what the fix is. A completed thread is worth 10 guesses !

 

[superdave]

I bet you have replacement terminals on the battery cables.

 

[ericinga]

Battery was the problem. The cell next to the ground terminal registered 0.6V. Should be 2.0V. I think it was likely dead and the jump start and charge helped open the circuit. All of the wiring is fine. Tested it with a DMM and had very little resistance.

Thanks for the comments.