Fuel gauge wire...? Location

[7.62]

It's been awhile since I've posted, over the last 2 months I've wrenched a new blueprint 355 engine into the truck. Lots of new parts etc.

I thought I had everything labeled and marked, well I've got one damn wire i didn't pay attention to.

It's pink in color, runs across the crossmember to the right side tank, but routes up towards the firewall. It has a small rubber junction and when separated one side has a pin.

My gas gauge pegs to the 3 o'clock no matter what tank I select, never had this problem before I tore everything apart. They always worked. The wife printed of some schematics for me and I just can't seem to figure it out.

It's a 1978 K10 with dual tanks short bed fleet side.

Any help would be greatly appreciated

Thanks much,
David.

I tried jumping the wire to both sides of the battery and that did nothing.

[1981Stepside]

IIRC, (and somebody jump in if I'm mistaken) the pink fuel gauge wire works on resistance, not power or ground. As a result, if the fuel gauge pins at full reading, then the circuit has zero resistance meaning the wire is grounded somewhere. I had the same problem when I bought my stepside and it turned out the P/O had squashed the wire under the box and it was finding ground through the frame. Sounds like you have a short somewhere.

[dieseldawg142]

yup, the pink is for your gauges, if the wire is crimped or crushed & touching metal, your gauges will go to 3:00. happened to me last yr.
easiest way, put a jumper from the junction to the sender, if it cures your problem start tracing the pink till you find the short

[7.62]

I've been looking for the camera to take some pics, wife has it stashed somewhere.

I guess a better way to ask is where this wire was terminated originally ????

I have the wires coming thru the frame, one is ground for each tank, terminated at the frame. And one each for the sending units going back to the plug in the firewall. It's this third wire in the harness I can't figure out.

It's more red in color.

I do appreciate your help so far.

[man7sell]

Mine is the opposite. The pink wire was broken and open circuit causing the gauge to read 3 o'clock. Shorting the wire to ground made it go to empty. When hooked up correctly the gauge read correctly. 76 Stepside

[motornut]

Yes
open pink is over full
Grounded is lowest point it goes on E

[greg64]

Try connecting the pink wire through a bulb to ground. This should make the fuel gauge read empty, assuming the ignition key is on. If it doesn't, the wire has a break in it somewhere.
Good luck!

[dieseldawg142]

Originally Posted by man7sell

Mine is the opposite. The pink wire was broken and open circuit causing the gauge to read 3 o'clock. Shorting the wire to ground made it go to empty. When hooked up correctly the gauge read correctly. 76 Stepside

yup, my bad, wrong wording. ultimately whats it really matter though, you still have to go trace out the problem in the wire harness wether it's been sliced, or grounded. considering even the newest square is over 20 yrs old now, why bother fixing old wires, go with new! instead of spending time chasing the wire, i replaced the pink from the firewall plug to the switching unit, took all of 10 minutes & had my gauge working again. i did go back later & fish the old pink wire out, one of the clamps had cut it...