electrical woes Options

[Mike1981]

Hello everyone

Hoping to get some electrical help on my 72

It has a V8 in it but will not pass any power

No buzzing of the fuelpump
No dash lights
No radio
no horn

nothing


I pulled the ignition switch and tested it

It was open until I turned the key and ohmed to almost 0 ohms
When I released it open circuit

Checked all wires in harness good

Ohmed out every fuse in the panel below dash as well as a few in the rear of the car.

Checked the ground strap (now a battery Cable)

At first I was not getting continuity between the tranny bolt and the body

Cleaned up the connection to the tranny as well as to the body ohms out to 2 ohms

Checked the battery 12.5 volts

Ohmed from neg terminal to chassis ground ohmed to 2-3 ohms

It was running fine yesterday until i turned on the headlights while staring it

then it died and I havent been able to get it to crank

Any help would be appreciated

thanks

MIke

[Spoke]

Do the lights come on with ignition off?

Do you have any electrical power on anything?

How about the 4-way flashers? They work with or without key in.

Did you clean the battery terminals?

How about the ground strap from battery negative to ground? Is it tight?

What is the battery voltage from positive terminal to chassis ground (not batt neg)?

[Mike1981]

Do the lights come on with ignition off?

Do you have any electrical power on anything?

How about the 4-way flashers? They work with or without key in.

Did you clean the battery terminals?

How about the ground strap from battery negative to ground? Is it tight?

What is the battery voltage from positive terminal to chassis ground (not batt neg)?

No lights at all

No power at all

4-way flashers do not work

re-cleaned battery terminals tight

battery neg to chassis ground 12.3 volts

re tightened ground strap to chassis and tranny

no power on fusebox under dash

3 vdc when key is off
0vdc when key is on

thanks for your help

[Spoke]

battery neg to chassis ground 12.3 volts

You mean battery POS to ground?

If battery NEG to chassis ground then there is no connection between battery NEG and chassis. What condition is the negative cable between battery and the chassis bolt above the battery?

If nothing works, then it's likely the battery or wiring, not your ignition switch or the engine ground strap.

Try this test:

Turn lights or 4-ways on.

Measure voltage across the TERMINALS of the battery, not the clamps. Touch the battery terminals.

Then measure voltage from POS terminal to POS battery clamp.
Then measure voltage from NEG terminal to NEG battery clamp.

Here we're trying to find where the battery voltage starts and where it ends since it's not making it to any components.