Fuel Gauge Wiring

[Obxff]

I have an issue with me 87 Winnebago Chieftan.    THe fuel tank swicth wont change anything.   I am a mechanic, but this chevy system cut up by winnebago is a little challenging.   Her is what I know.

Chevy originally put a relay near the fan shroud for the fuel pump. This works as it should, with crank circuit and oil pressure switch. Even gives power to the tan and white wire that should run the pump.

The tank selector switch activates two bosch type relays to switch the gauge wiring and somehow turn the pump circuit off. I know that if i take this out of the loop and connect the original pink wire back to the fuel gauge it works as it should.   

The relays get their main power through two orange wires. Mine dont have power and it seems to be a pain in the but to figure where they get it.  This in turn wont switch gauge sending units, and the fuel pump wont run, so some where this system breaks the rear fuel pump circuit if using the auxiallry tank.   

I would be completely happy with two fuel gauges, which wire is for the auxiallry tank sending unit?

Next where does the break occur to the rear fuel pump? I will be happy to give it its own circuit and do away with the winny part.   Any help would be appreciated.

[gadgetman]

So you have a problem with the orange 12 feed wires. You may have a corroded fuse block connection or a blown fuse link for the orange wires. I dont have a wire diag. Easy fix would be to cut the orange wires at the relays and supply it with a new fused circuit.

[Obxff]

Your right but thats the easy part, the other side is where the fuel pump feed  breaks.   

[DaveVA78Chieftain]

Because this year chassis uses a fuel return line, you have a 6 port fuel selector valve.  Parts book for your rig confirms the the valve is installed.



Here is a typical wiring diagram for 6 port fuel selector valve.  Hopefully it will help you work this out.

http://econtent.autozone.com:24999/znetcs/psb/en_US/2/0/1765/selector_valve_installation.pdf


Dave

[cncsparky]

I have an auxilary tank also, but it is only for generator fuel (10 gallons I think).  The switch on the dash on mine only switches fuel sender wires to read fuel level in the aux tank, no fuel pump in the aux tank.  Is your aux tank set up to fuel the chassis engine?

[Obxff]

Got it all figured out.  It was actually an issue with the original gm pump relay. If it doesn't work the relays that operate the remainder of the system aren't activated.   So thanks for the replies and it's a simple but stupid system.   Would have been easier with two fuel gauges to simplify part of the process.