Electrical Issues... Need help!!!

[toBURKEulosis]

The other day I was driving to work in my 1972 and I stopped and started to roll again when the battery died. I couldn't get it started so I had to get it towed back to my house. Once, there I started looking at the battery and it was dead so I charged it and out it back in and the truck started. So I figured it was just the battery. The following day I started it up and it was warming up and the it died again. I checked the battery and it was dead. So I figured it was alternator. I installed a new alternator and charged the battery and tried to start it this time and the following happens:

1. Turn key to AUX. Gauges and fan come on.

2. Try to start truck it the starter clicks three or four times, and then all power dies.

3. Turn key to off and turn back to AUX. NO POWER.

I took my battery to Autozone and got it checked and it's all good with 100% charge. Also I couple of weeks ago I got a new starter. I don't know where else to look. Please help me out.

[c10srule]

ive had a similiar problem on a chevelle and ended up the hot cable was corroded under the insulation

[VetteVet]

Assuming your battery cables and posts are clean and tight and the positive cable is clean and tight at the starter. Check the negative cable where it grounds to the engine and run a ground to the frame from the engine.

Next check the power from the battery positive cable terminal to the junction bolt on the right fender. The small wire that goes there contains a fusible link which can burn out and not supply power to any point in the truck. If you temporarily jump this wire and you get power back then you'll need to replace this link. Make sure you do not have a short in the wiring or it will blow again.

There should be another 12 gauge red wire connected with the fusible link and possibly a small black wire if you have the gauge dash and not the idiot light dash. This red wire carries power to a four way junction where the alternator large wire and the regulator red wire and another red wire join. There is another red wire from there to the cab that carries all the power to the cab. It will be seen in the firewall junction block.

From there it goes to the key switch, the fuse panel, the ignition switch, the headlight switch and the horn relay. This will be the key off power circuit. You can check for power at any of those points and tell if the circuit is alright. If the horn blows it means there is power to the cab provided there is nothing wrong with the horn relay circuit.

If all these points check out then I would look at a bad key switch.

Here is a diagram showing what I have just described.
This is the engine bay.



This is the inside of the cab to the horn relay and the fuse panel.



and this is the key switch and the headlight switch. Just follow the red wires.

[toBURKEulosis]

Update:

I found that the positive terminal was all burn up due to the previous owner red necking all the wires (i.e. twisted wires wrapped in electrical tape, exposed wire, frayed ends etc.)

I replaced all the wire and checked that the battery is charged and the starter is getting power.

Now for the weird part. Even though the ignition cable is hooked up properly, when you turn the key nothing happens. No lights, no fans, no starting. I checked the fuses. No blown fuses and the ignition slot runs straight through without a fuse.

Any ideas?

[FLEET72]

Originally Posted by toBURKEulosis

Update:

I found that the positive terminal was all burn up due to the previous owner red necking all the wires (i.e. twisted wires wrapped in electrical tape, exposed wire, frayed ends etc.)

I replaced all the wire and checked that the battery is charged and the starter is getting power.

Now for the weird part. Even though the ignition cable is hooked up properly, when you turn the key nothing happens. No lights, no fans, no starting. I checked the fuses. No blown fuses and the ignition slot runs straight through without a fuse.

Any ideas?

Did you check the fusible link as circled in VetteVet's post?

[toBURKEulosis]

Is the junction block where all the fuses are? If not I don't know where to look.

[toBURKEulosis]

I replaced the blown fuses in the fusible link and the power came on aux and i turned the key and nothing happened and now the the power won't come on again. I checked the fuses and they are fine. Then I followed the red wiring and it all looks right... I don't know what the do next.

[VetteVet]

1. blow the horn
2.turn on the lights
3 do the brakes work?
4. does the dome light work?
If none of these work then the main power from the battery is bad.

If they work then your key switch is bad.