No power at some locations in fuse block

[eightyduce]

Fixed it was a broken spade connector on the back of the fuse block it came off the male connector

You must be registered for see images attach

I can’t figure out what the problem is 77 c10 is not getting power in the fuse block under the dash to the cluster feed, PNL lights and directional signal spots. I put in a 383 crate motor and swapped it to a one wire alternator set up. The truck starts, but when I went to hook up the fuel tank, the fuel gauge did not work in the dash I pulled the cluster out and using jumper wires under the hood. The fuel gauge worked. I then realized there was no 12 V power coming through the pin connector on the back of the cluster gauge so then I checked the fuses that’s when I realized there is no power at those locations. I also swapped out the original engine wiring harness for one off of a 77 suburban that had all the wires that I needed except for some of the sensor wires, which I didn’t want anyway to clean up the engine department. I can’t figure out what the problem is. Any suggestions?

You must be registered for see images attach

 

[Broken85]

You must be registered for see images attach

Try checking continuity across the accessory circuits in the fuse box to see if you have a burned cross over, but I doubt it. I think you will probably find the problem someplace in your wiring harness swap. This may atleast tell you what wire to trace.

 

[CalSgt]

There are two red wires on the bullhead in the engine bay that supply different circuits with 12v battery power in the truck. IIRC they are about 10 Ga wires.

I cant remember the exact routing of them but i think they came off of the junction block on the firewall just to the left of the brake booster and the other down to the battery lug on the starter. one of them split off to my alternator also.

These wires have fusible links at the junction block and down at the starter.

Some possibilities:
one of these red wires didn't get hooked up when you changed the engine harness
One of the fusible links is blown or damaged
It is not uncommon for the bulkhead spade terminals to burn up where the red wires pass through, but I assume you would have noticed when you swapped to the different engine harness
With other styles of electrical connectors it is common to bend a pin, never heard of that issue on SB bulkhead connectors but worth mentioning

 

[Bextreme04]

I can’t figure out what the problem is 77 c10 is not getting power in the fuse block under the dash to the cluster feed, PNL lights and directional signal spots. I put in a 383 crate motor and swapped it to a one wire alternator set up. The truck starts, but when I went to hook up the fuel tank, the fuel gauge did not work in the dash I pulled the cluster out and using jumper wires under the hood. The fuel gauge worked. I then realized there was no 12 V power coming through the pin connector on the back of the cluster gauge so then I checked the fuses that’s when I realized there is no power at those locations. I also swapped out the original engine wiring harness for one off of a 77 suburban that had all the wires that I needed except for some of the sensor wires, which I didn’t want anyway to clean up the engine department. I can’t figure out what the problem is. Any suggestions?

You must be registered for see images attach

Either one of the fusible links from the starter is blown, you forgot to hook one of the three wires up, or there is a break in the line somewhere. The fuse block gets all of it's power entirely from the smaller 12 Ga wires that connect to the starter with fusible links in between. It is common for someone to connect only one of those wires, or for one of the fusible links to be bad, which then only powers half the panel. It is also possible that you have a bad ignition switch.

 

[Radiohead]

I see one wire alternator and immediately go back to how the wiring from the field circuit got handled.

Otherwise, all the previous posts are spot on as well.

 

[Scott91370]

Also, make sure the bulkhead is connected tight. Mine was slightly loose and it would do some crazy things.