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]

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.

Thank you

 

[Daniel6895]

Hi everyone thank you all for you guys help. I went ahead and traced that second to the last wire in the picture I circled and it connects to the power cord to the alternator. I tested that wire to make sure and at idle it would read normal around 14s and then for about 5 seconds randomly drop down and back up every two to three minutes the same way it did when i tested the other end. . Would that happen to be a bad alternative or regulator? It doesn't have a problem starting and the battery meter is automatically to the middle when it starts. Bright lights everything . Idled for thirty minutes straight with music on all lights doors open . Just when it's in drive and applying just the right amount of gas the electric flickers out like it's not getting enough juice. Im going to try and check more wiring later tommarrow.

 

[Schurkey]

traced that second to the last wire in the picture I circled and it connects to the power cord to the alternator. I tested that wire to make sure and at idle it would read normal around 14s and then for about 5 seconds randomly drop down and back up every two to three minutes the same way it did when i tested the other end... ...Just when it's in drive and applying just the right amount of gas the electric flickers out like it's not getting enough juice.

First Guess: There's an intermittent connection to the alternator, which is pulled open when the engine is torquing-over on the rubber engine mounts. This connection would be the SMALL, probably single wire that plugs into the side of the alternator (not the big wire connected to the rear.) This wire terminates in a four-wire molded plastic connector plugged into the alternator, but that "four wire" connector may have only this one wire actually attached.

If you trace that small wire, look for a break or burned spot in the insulation, or a loose connection at one end or the other.

 

[Daniel6895]

Man thank you and everyone else before you I went over to look at the engine mounts and grounds and what you said again and man I over looked this little guy in the pick idk how many times. Hopefully it fixes the problem. This could explain why I started having this problem whenever I went over the railroad tracks on the way home from work.

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[Schurkey]

I will be somewhat surprised if fixing that ground strap cures the alternator/charging issue.

But goofy things happen. Good luck.

 

[GoToGuy]

This intermittent loss of power, does truck loose power as if the key shut off. Or is just power to instruments and some lighting. This could also be a connector that was not fully closed and latched/ locked. As a jarring , rough motion causes the contacts within the connector to separate then come back together.
Running the engine in park having some helper move the throttle up and down slowly while moving a wire bundles at or near the throttle cable. Observe for replicate problem . Also check under the dash while moving the throttle cable does it touch anything or flex or move anything. Is the ground at the OBD connector loose and or tight. There is another ground up against the firewall.

 

[Oakr11]

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 ?

I would double triple check the fusible links feeding the fuse block. I’d start by putting my test light on the terminal and wiggle the wires until I found one that came and went when I shook the wire.
The power for that block come directly from the positive battery terminal. Then another wire goes from the block to fuse block.

 

[Oakr11]

This intermittent loss of power, does truck loose power as if the key shut off. Or is just power to instruments and some lighting. This could also be a connector that was not fully closed and latched/ locked. As a jarring , rough motion causes the contacts within the connector to separate then come back together.
Running the engine in park having some helper move the throttle up and down slowly while moving a wire bundles at or near the throttle cable. Observe for replicate problem . Also check under the dash while moving the throttle cable does it touch anything or flex or move anything. Is the ground at the OBD connector loose and or tight. There is another ground up against the firewall.