Aceofspades427

Hello. I've been working on my neighbors 77 corvette and I'm having a crazy electrical problem and was wondering if anyone knew of any common problems or suggestions

so here's the deal, this car has been off the road for 8 years and sometimes when you turn the key to ignition on it actually turns on but most of the time it doesn't. And if you try to actually start the car nothing happens and the car loses all power.

Some additional information, the negative battery cable has 12 volts so I know there's a short to ground somewhere but we have no idea where. we have already checked the ignition switch, neutral safety switch, and the alternator.

thanks for any help

henrikse

SO when you put neg meter lead on battery - and touch the positive cable to a ground you get 12 volts? If you have a short you will have to put an ammeter on and see how much current it is drawing? With ammeter in start removing fuses to see if you can isolate

txfatboy1

Sounds like you may have a badly corroded negative battery cable connection either at the battery or at the frame..... or both. Keep in mind just because the outside of the connections may look okay, doesn't mean there is enough good contact to allow high current flow. Make sure all cable connections are clean metal..... and that there is no corrosion inside the battery cables.

Aceofspades427

No when i touch one end to neg post on battery and the other to the neg battery cable or the frame there's 12 volts.

and that was my next plan of action, I just posted here to see if there was any super common C3 problem

Aceofspades427

But that doesn't explain why I have 12 volts coming from the negative battery cable

txfatboy1

wouldn't that mean you have no connection between the battery terminal and the battery cable... or very high resistance?

lionelhutz

The negative post of the battery isn't connected to the frame. You either have a dirty connection or a bad negative battery cable.

bruiser

henrikse

Aceofspades427

But why would that give me 12 volts on my negative battery cable and every piece of metal on the car

lionelhutz

It's what happens when you disconnect the negative cable.

Take your booster cables and connect one of the negative clamps to a good bare metal spot on the engine, feed the cables through the passenger window and connect the other negative clamp to the battery. The problems will all go away.