I have a 92 c1500 that has no constant 12v to the power fuse/cab . When applying gas at a certain point electricals and radio flickers off/ back on.

[Daniel6895]

I have a 92 c1500 that has no constant 12v to the power fuse/cab . When applying gas at a certain point electricals and radio flickers off/ back on to wear the engine almost cuts off but when letting off the gas everything goes back to normal even in park. Applying the right pressure if gas keeps the truck running . Looked at the junction box and getting constant 12v to all wires except for the second from the last towards the right. I also tested the power fuse in cabin and it constantly jumps up 12vs and back down to 0volts just like the wire i mentioned earlier in the junction box.

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Would this be connected in any way ?

 

[CumminsFever]

It makes me think it's poor ground. I've seen grounding issues do the stupidest, most unexplainable things.

 

[movietvet]

Like @CumminsFever said, sounds like a ground issue, especially if in a salt road state. I would start by disconnecting the battery and then disconnect the circled wiring at the pic and clean and tighten. Then look at bot battery cable ends for crud/corrosion. Make sure when you reinstall the battery cables that you tension properly. Also, look under the cable insulation close to the ends, for corrosion built up under the insulation.

 

[Schurkey]

I'd have said it was on the supply side, not the ground side. I'd be looking at the other end of the fusible link in your photo. Bad ground wouldn't kill voltage at the distribution block.

I bet the fusible link is damaged--intermittent. Thinking the one you have circled is the one that leads back to the starter motor, and from there to Battery +. But you'll find out for sure when you start tracing that larger-gauge wire.

 

[Erik the Awful]

Yup, just a couple weeks ago I had to troubleshoot my son's truck. He'd struggled with power cutting in and out, but he never fixed it, so it finally lost all power. I replaced the wire that runs down to the engine and up the firewall with one that just runs over the fender. Personally, I think GM's routing is absolutely horrible and was done just to make the harness easy to install at the factory.

Don't forget that the first few inches of the wire are fusible link. It's cheap and readily available at your local auto parts store.

 

[Daniel6895]

Yup, just a couple weeks ago I had to troubleshoot my son's truck. He'd struggled with power cutting in and out, but he never fixed it, so it finally lost all power. I replaced the wire that runs down to the engine and up the firewall with one that just runs over the fender. Personally, I think GM's routing is absolutely horrible and was done just to make the harness easy to install at the factory.

Don't forget that the first few inches of the wire are fusible link. It's cheap and readily available at your local auto parts store.

Thank you so much. I'm going to give that a try tommarrow morning.

 

[Daniel6895]

Yup, just a couple weeks ago I had to troubleshoot my son's truck. He'd struggled with power cutting in and out, but he never fixed it, so it finally lost all power. I replaced the wire that runs down to the engine and up the firewall with one that just runs over the fender. Personally, I think GM's routing is absolutely horrible and was done just to make the harness easy to install at the factory.

Don't forget that the first few inches of the wire are fusible link. It's cheap and readily available at your local auto parts st

I'd have said it was on the supply side, not the ground side. I'd be looking at the other end of the fusible link in your photo. Bad ground wouldn't kill voltage at the distribution block.

I bet the fusible link is damaged--intermittent. Thinking the one you have circled is the one that leads back to the starter motor, and from there to Battery +. But you'll find out for sure when you start tracing that larger-gauge wire.

Thank you sorry for replying late. I forgot to mention the photo isn't my own photo was the closest I can get too to what mines look like do to me not being near the truck at the time . Just recently purchased truck not too long ago from family member and noticed once you mentioned the fusible links that some of the wires doesn't have any such as the one I circled in the picture but was reconnected with a butt splice . On one end of the butt splice wire was exposed and turning green . I recut the wire but haven't had the chance to get a new one at the moment yet so since then but I'll definitely be tracing that wire tommarrow because I did retouch the wire to the panel in the picture but the problem still stayed the same with voltage dropping and going back up.

 

[Daniel6895]

It makes me think it's poor ground. I've seen grounding issues do the stupidest, most unexplainable things.

Thank you

 

[Daniel6895]

Like @CumminsFever said, sounds like a ground issue, especially if in a salt road state. I would start by disconnecting the battery and then disconnect the circled wiring at the pic and clean and tighten. Then look at bot battery cable ends for crud/corrosion. Make sure when you reinstall the battery cables that you tension properly. Also, look under the cable insulation close to the ends, for corrosion built up under the insulathan

Like @CumminsFever said, sounds like a ground issue, especially if in a salt road state. I would start by disconnecting the battery and then disconnect the circled wiring at the pic and clean and tighten. Then look at bot battery cable ends for crud/corrosion. Make sure when you reinstall the battery cables that you tension properly. Also, look under the cable insulation close to the ends, for corrosion built up under the insulation.

Thank you so much will be checking

 

[movietvet]

Yup, just a couple weeks ago I had to troubleshoot my son's truck. He'd struggled with power cutting in and out, but he never fixed it, so it finally lost all power. I replaced the wire that runs down to the engine and up the firewall with one that just runs over the fender. Personally, I think GM's routing is absolutely horrible and was done just to make the harness easy to install at the factory.

Don't forget that the first few inches of the wire are fusible link. It's cheap and readily available at your local auto parts store.

Oh yea, GM will do whatever makes it easier to assemble at factory. Designers/engineers do not work on them. That has been going on for oh so many years. That is why so many techs in shops cuss those same designers/engineers.