I've got a 1990 S15 Jimmy. The fuel is not pumping. I checked the harness at the fuel tank connection with a circuit tester and there is no power. I checked my Haynes manual but there is no wiring diagram for the fuel system. Can anyone give me any ideas on what the problem could be or a wiring diagram of the the fuel system?

Should check the fuel pump relay.

Should check the fuel pump relay.

Please forgive my ignorance but, where is it located?

Should be oe of the two located on the top of the firewall.

I'll check it out! Thanks!

I put on a new relay and it still won't pump fuel.
I also noticed that I don't have any headlights and running lights either.
Any suggestions/ideas?

u got any electricity?

I put on a new relay and it still won't pump fuel.
I also noticed that I don't have any headlights and running lights either.
Any suggestions/ideas?

I've got power to the blower motor but, the radio, courtesy, cargo, and all of the other lights are not working at all.

The engine even cranks!

I've checked all of the fuses and the wiring but, I can't find anything wrong.

hold on, check the battery voltage.

Everything else works fine, power door locks, windows etc. The engine cranks great except it can't start because the fuel is not being pumped.

The battery is brand new and has 13 volts.

The following are not powering up: Head and running lights, glass hatch power release and the fuel pump.

I have checked all of the fuses and the wires and I can't find anything wrong.

Check your fusible links near the battery.

All of the fuse links are good too.

Any one have a wiring diagram?

I'm wondering if I've missed looking at some wires or something.

ok, there might be a fuse in the fuse panel for the fuel pump.

I went through the fuse panel again and checked all of the fueses and they're all good.

The lights, windshield wipers, rear hatch (glass electric release) and the fuel pump are the only things not getting any power.

I can't figure this out!

Ignition switch.

I checked the ignition switch and it is good too!

This thing is really pissing me off.

How did you check it?

I used a circuit tester on the feed side and then on the supplied side with key off, on run and then on accessory.

I used a circuit tester on the feed side and then on the supplied side with key off, on run and then on accessory.

Ummmm.....

That is not how you test it.

Just replace it, I can almost guarantee it is your problem.

I have replaced the following; both light and pump relays, fuel pump, ignition switch (key cylinder and column switch). I took the fuse panel out and cleaned the bulkhead connector (both sides) and the fuel pump still wont activate.

oil pressure/fuel pump switch.LOcated in the bak of the engine by the firewall.Its about three to four inches long with a wire clip.Three wires.
To the right and below the distributer.It screws into bloke below the intake manifold. THe oilpressure switch cuts the electricity to the fuel pump off when it thinks there is very little or no oil pressure.Keeps the engine from blowing if oil pressure dorops.I hope this helps.LEt us know.