Rookie Quuestion - Wiring Related

[Pontitruck]

Hi guys,

I am working on running the electrical for the rear lights, fuel pump and sender on my 65 GMC project. Where does the wiring go to? I assume it comes in the cab somewhere but I can't see the obvious. Of course the person that started this project may have covered it up, I'm starting with no knowledge as it was just a cab, front end and bed on a frame when I started.

Thanks for the help!
Joe

[PGSigns]

Well they did not have a fuel pump wire so just run it with the harness. That ran from the fire wall down to the frame on the drivers side to the back of the bed. There was a harness for the tail lights at the back. The fuel sending unit wire ran down the edge of the sil plate along with the wiring for the inside light and then along the top of the tank. I have a wiring harness out of a 65 GMC that is almost complete if you need one.
Jimmy

[raidmagic]

I ran all that wiring out of the fire wall and straight down to the frame rail. I ran it along the frame on the inside attaching it with rubber coated straps and tek screws when I rewired my truck.

[Pontitruck]

Thanks for the replies.
I have the American Autowire kit so I'm making it from scratch nearly. When you say from the firewall do you mean in the engine compartment? If so what connector and any pics would be appreciated

[PGSigns]

If you have the classic update harness for the truck just follow the instructions. The harness for the back plugs into the plug that is on the drivers side of the fire wall. The wiring for the sending unit in that kit has it running in the stock location. What I did was to bring it out the fire wall along with fuel pump power through the grommet for the oil pressure line. I then used the fuel pump wire to trigger a relay to power the fuel pump. The wiring ran across the fire wall and was added to the harness running to the back.
Jimmy

[Pontitruck]

Originally Posted by PGSigns

If you have the classic update harness for the truck just follow the instructions. The harness for the back plugs into the plug that is on the drivers side of the fire wall. The wiring for the sending unit in that kit has it running in the stock location. What I did was to bring it out the fire wall along with fuel pump power through the grommet for the oil pressure line. I then used the fuel pump wire to trigger a relay to power the fuel pump. The wiring ran across the fire wall and was added to the harness running to the back.
Jimmy

Jimmy,

Thanks for the help. My harness is missing any instruction for the rear. It came with the project. I did complete the front harnesses and they both plug into the plug that comes through the firewall so there is no place for the rear to plug in.
Joe

[Pontitruck]

Originally Posted by PGSigns

If you have the classic update harness for the truck just follow the instructions. The harness for the back plugs into the plug that is on the drivers side of the fire wall. The wiring for the sending unit in that kit has it running in the stock location. What I did was to bring it out the fire wall along with fuel pump power through the grommet for the oil pressure line. I then used the fuel pump wire to trigger a relay to power the fuel pump. The wiring ran across the fire wall and was added to the harness running to the back.
Jimmy

Jimmy,

Thanks for the help. My harness is missing any instruction for the rear. It came with the project. I looked on AAs website and they don't show a PDF of the rear harness for some reason. My kit is a 500560. I did complete the front harnesses and they both plug into the plug that comes through the firewall so there is no place for the rear to plug in. Here's a pic
Joe

[PGSigns]

I have a kit at the house and I will pull the instructions out and see what it shows for the back. Been several years since I did the 65 so a memory jog will be good. I will post pics of the instructions if it looks like you have some missing.
Jimmy

[BR3W CITY]

When I was doing my LS swap, I got annoyed at the body side wiring harnesses, and decided to rip out all of the wiring from the firewall back to redo it.

I grabbed a wiring cart, and just decided to build my own wiring from the ground up. It was honestly easier than figuring out the 40+ years of solid core wiring splices and double-doubled butt connecters. IIRC it was less than 12 wires total .

[straight6chevyguy]

These trucks are so darn simple I would never be afraid to to rewire the whole truck from scratch!

[Clyde65]

Mine runs from the plug on the firewall, angles (with a clip) down the cab to the drivers side frame rail, runs down it until the end of the plug. Your fuel sending wire used to be inside running in DS wiring run under the door sill, then back to the tank. I hope this helps. Good luck.

[Pontitruck]

Thanks guys, I wired the rear today and used a hole in the lower firewall the bring the wires out.

[PGSigns]

I looked at my 66 this morning and the wiring comes out through a hole over by the throttle linkage. Runs down to the frame and to the back.
Jimmy

[Pontitruck]

Originally Posted by PGSigns

I looked at my 66 this morning and the wiring comes out through a hole over by the throttle linkage. Runs down to the frame and to the back.
Jimmy

Thanks Jimmy, I found that spot this past weekend and got the rear harness installed.
Thanks again
Joe