Electrical help

[JAM1777]

I took your guys advice and got my drum brake system repaired till i could afford disc brake conversion, and it was a well spent $400!! Truck stops excellent! Now i have another problem, when i drive the truck all the power goes out.....sometimes in the middle of a busy intersection. I put the truck in park and when i turn the key the engine will turn over but takes a few turns of the key to start. I told the mechanic that fixed my brakes about this problem and it happened to him too when he was test driving after he fixed the brakes. So he changed the coil and igniter, thinking that would fix the problem.......and he also checked all my connections and he said some were loose. He said he hopes that fixed the problem but he didn't know for sure. When i picked up my truck today i drove from the mechanic hoping it was fixed, and as soon as i got close to my house I was waiting at a red light and it died again! It started right up when i turned the key. Im not sure what to do or check?? Any troubleshooting ideas or advice would be very appreciated

[WIDESIDE72]

Clean and tighten all of your grounds; battery to block, block to cab. There areothers but they wont keep the truck from running if loose broken or corroded.

[JAM1777]

Ok, the engine is a new crate. It has only 2000 miles on it..will that make a difference?

[VetteVet]

You need to find out which one of these three things is happening.
1. You are losing all electrical power, no horn, no wipers, no lights, no radio etc.
2. your engine is losing ignition power and the engine is just dying.
3. Your fuel system is at fault and the engine is just stalling.

If it's no.1 then there's only five places that will cause that.
1. your negative cable on the battery may be loose.
2. The negative cable ground on the engine may be bad or loose.
3. The positive cable on the battery may be loose.
4. The fusible link from the positive terminal on the battery to the right fender junction bolt may be loose or the wires inside may be broken.
5. The wire from the fender junction bolt to the four way connection on to the firewall block and into the cab may have a bad connection at the four way or in the firewall block.

If you're not losing all the power then it might just be a bad key switch or the ignition wire to the coil may be loose.

If you're just running out of gas then you'll still have power to the horn, lights, etc. You may not notice those if you just start the engine right away. Having to crank it a bit is a symptom that it has run out of gas and takes a minute to pump it back up to the carburetor.

[JAM1777]

When it shuts off the radio goes dead and then the engine dies.

[JAM1777]

Originally Posted by VetteVet

You need to find out which one of these three things is happening.
1. You are losing all electrical power, no horn, no wipers, no lights, no radio etc.
2. your engine is losing ignition power and the engine is just dying.
3. Your fuel system is at fault and the engine is just stalling.

If it's no.1 then there's only five places that will cause that.
1. your negative cable on the battery may be loose.
2. The negative cable ground on the engine may be bad or loose.
3. The positive cable on the battery may be loose.
4. The fusible link from the positive terminal on the battery to the right fender junction bolt may be loose or the wires inside may be broken.
5. The wire from the fender junction bolt to the four way connection on to the firewall block and into the cab may have a bad connection at the four way or in the firewall block.

If you're not losing all the power then it might just be a bad key switch or the ignition wire to the coil may be loose.

If you're just running out of gas then you'll still have power to the horn, lights, etc. You may not notice those if you just start the engine right away. Having to crank it a bit is a symptom that it has run out of gas and takes a minute to pump it back up to the carburetor.

Ok i can figure out the first 3 but not sure what 4 And 5 are? ? What is the fusible link? Is it a part i can buy at the local auto store and replace? ? And not sure what the wire from the fender junction bolt to the four way connection on to the firewall block is??

[VetteVet]

Originally Posted by JAM1777

Ok i can figure out the first 3 but not sure what 4 And 5 are? ? What is the fusible link? Is it a part i can buy at the local auto store and replace? ? And not sure what the wire from the fender junction bolt to the four way connection on to the firewall block is??

Well if you have a stock wiring harness that hasn't been modified or hacked up, then you should have a small wire going from the positive battery terminal over to the right fender to an insulated bolt mounted in a hard plastic holder.

This wire carries all the positive voltage from the battery and it is made so that it will break the flow of current if a large short occurs in the truck wiring. It protects the wiring in the harness in case that happens.

There should also be a red 12 gauge wire connected there that joins the battery voltage to the alternator output voltage for charging and another red wire that goes to the firewall junction block that carries power to the cab for the fuses, ignition, lights, and horn. you can purchase the fusible link at any auto parts store and it should be 30 amps or more.

The red wire is used to carry battery current to the connection I described and to the rest of the truck circuits. It runs from the fender bolt across the top of the radiator and down to the connector. See the pictures below.

This is the fusible link to the fender junction bolt. There's two pictures.



And




This is the connection where the red wire runs across the top of the radiator and solders into.



Then there is a red wire that goes to the firewall block by the master cylinder that carries all the battery and alternator voltage for the truck. If there is a bad connection inside the firewall block to the other side of this red wire then you'll lose all power as well.



This is the terminals on the inside of the block.