PO converted 1982 6.2 k10 to gas....with wiring problems

[Danvis]

Ill come back to this thread later becuase one day it may get rewired. But for now any help is appreciated. May be lengthy but gonna try to be thorough.

Fuel gauge doesnt work. All of the following led me to find this plug coming from the selector switch not plugged into anything. Normally id plug it in and see if it fixes my problem but wanted to see what yall thought. Not knowing if it would even be a reason for a my fuel gauge to not work and being unsure if it was unplugged when it was changed from diesel to gas for a good reason or not but want to be sure im not gonna pump diesel to my motor because i dont know if the other tank was swapped or only one tank....if it wont fix my gas gauge what is it for.

Cleaned ground and frame by the tank. Checked the printed circut for the gauges. Should be a new..ish sending unit so i havent went through the trouble of dropping the tank yet......last resort because dont know the conditions of the passenger side tank so at some point id like to change both tanks and sending units and atleast the lines from the 2nd tank unless i dont understand how its plumbed correctly i dont know how the lines from that tank to the selector valve are either.

Also any help with what wiring harness i should get im a little unsure...i read alot of good about the painless and for something like wiring that i want to last a long time the price isnt completely insane. But the truck was originally a 1982 K10 6.2 diesel with an auto trans. The guy before the guy i got the truck from swapped it to a 1982 k10 with 350/sm465-np205 with a 10 bolt 8 lug front and what i was told was a newer e350 srw D60 rear. Is the harness from painless designed for auto or manual as far as neutral safety, reverse lights. Not a have to have for myself but if im going to go through the trouble of rewireing id like to do it all not parts

[hatzie]

Usually you're better off to fix the sections of the original harness that are damaged than to buy a one-size fits none harness.
Just do it one section at a time so it's not a massive job.

Parts of the harness like the tail lamps & fuel-gauge wire, forward lamps, HVAC, and the NL2 dual fuel tanks are actually completely self-contained sub-harnesses that plug into the main harness at various points. If one of these is damaged it's fairly straightforward to swap in an undamaged sub harness or just fab a new one. The cab to taillamp harness is an easy one to cut your teeth on. Four wires...

The plug in pictures 1 & 3 is the disconnect for the valve to switch wiring. The Green wires run the shuttle motor on the valve. The third wire is the diesel only water-in-fuel wire from the senders. Later years moved the WIF sensor to the Stanadyne 80 fuel filter cartridge on the firewall.
The Pollack valve also has three more wires running to an internal-to-the-valve switch that handles switching senders to the fuel gauge.
This thread should answer any questions about that system. 1982 is covered in post #2...
http://67-72chevytrucks.com 73-91 Dual Tanks Theory of Operation

[Danvis]

Originally Posted by hatzie

Usually you're better off to fix the sections of the original harness that are damaged than to buy a one-size fits none harness.
Just do it one section at a time so it's not a massive job.

Parts of the harness like the tail lamps & fuel-gauge wire, forward lamps, HVAC, and the NL2 dual fuel tanks are actually completely self-contained sub-harnesses that plug into the main harness at various points. If one of these is damaged it's fairly straightforward to swap in an undamaged sub harness or just fab a new one. The cab to taillamp harness is an easy one to cut your teeth on. Four wires...

The plug in pictures 1 & 3 is the disconnect for the valve to switch wiring. The Green wires run the shuttle motor on the valve. The third wire is the diesel only water-in-fuel wire from the senders. Later years moved the WIF sensor to the Stanadyne 80 fuel filter cartridge on the firewall.
The Pollack valve also has three more wires running to an internal-to-the-valve switch that handles switching senders to the fuel gauge.
This thread should answer any questions about that system. 1982 is covered in post #2...
http://67-72chevytrucks.com 73-91 Dual Tanks Theory of Operation

Ok thanks. So plugging it in SHOULD make the gauges work. I downloaded all the links you have available for my truck . Are they different for the diesel models

[hatzie]

No. That plug is only the power to the valve motor on motor plug terminals D & E.
The gauge is a separate problem. If you look at the theory of operation thread it'll show the gauge wiring to terminals A B & C.

[Danvis]

Alright. After doing some searching through a hack job of wiring(all the previous desiel stuff was cut here and cut there and shoved back where you cant find it instead of removing it) i traced down the pink(from selector valve to gauge) and pink/white(from selector valve to drivers tank) and spliced them together, bypassing the selector valve. That made my gauge start reading for now which was the goal since the pass tank is still diesel. Im assuming there is an issue at the selector valve but ran out of time to trace anymore. Ill be going back and fixing all the wiring when i replace the tanks and senders in a few months.

Hope this helps somebody. Side note...i seen a chart a while back showing the different problems fuel gauges have based on the needle postion. Was said to be a ground issue if it was pegged past full which is what mine was doing.