No power issue

[G-Bodydude1983]

So I have a 1986 c-10, I have never had any issues with it what so ever but when I tried to start it the other day and it had no power at all to anything. I have measured the voltage across the battery terminals to be 12.6 but if I go from the positive terminal to a body ground it only reads 8 volts. I have checked numerous wires in the cab and they all only read 8 volts as well. What would cause the battery terminal to termail to read normally but positive terminal to chassis ground only read 8 volts? I did the same measurements on my el camino and regardless of location of the ground either on the negative terminal or a chassis ground it always reads 12.6 volts

 

[86LK]

does it turn over? what's the Amperage measurement?

 

[G-Bodydude1983]

does it turn over? what's the Amperage measurement?

It has no power to any systems what so ever, no lights, no starter, no anything at the moment

 

[Clone TIE Pilot]

Either a dirty ground connection somewhere or dirty or faulty battery cables.

 

[airboatgreg]

Pull and inspect, clean both battery terminals first.

 

[86LK]

if you pull both negative and positive cables as airboatgreg says, then use a multimeter to check for Volts and Amperage, I suspect you will find Zero Amps, or close to it. my experience has been that anything less than 25% of rated CCA will get you nothing, and you typically need at least 50% of CCA just to turn an engine over

 

[abbey castro]

A ground may look ok, but... corrosion will stop it dead on its tracks! Take apart all the grounds and clean the surfaces and reinstall. There are never too many grounds! Ground straps from block to frame, to body, headlight harness to radiator header panel, and so on. Don't forget the battery cable to starter and ground to frame or engine block! Ground or lack thereof are one of the biggest gremlins (not like in AMC Gremlin) of cars electrical systems. As for the battery it needs to be checked with a battery tester. I've tried with the multi-meter and have not been successful with that process. Checked OK with multimeter but wouldn't crank! New battery solved all problems. Good Luck! Let us know how it goes.

 

[Rt Jam]

Do you know how to check voltage drop? You have a bad connection somewhere.

With your meter on volts. Place one lead on Battery post, one on battery connection. Should read zero or almost zero. Next move the lead from battery terminal to where it's connected. It should read zero. Keep doing this and somewhere it will read 4 volts (12 - 8 )