Ok, Ive been troubleshooting for the past 3 hours.

- When I check voltage at the purple-white wire going to the relay with the neg battery post I get 12.5v

- when I check voltage at the inertia switch and fuel pump connector, they go to about 6 for the first few seconds of key switched to on, then steadily increase

- when I connect the battery directly to the pump, nothing happens


Is this a bad fuel pump?

12.5v at PW wire from fuse box is good. Can pull fuse F6 in engine comaprtment fuse box to verify where you are.

Read volts from either side of inertia switch to negative battery post. Should see 12 Volts when key is turned on for a few seconds. ECU times out pump if truck not running. To protect pump and you.

If you are trying to connect 12 volts at the pump, would need to put (+) volts on pin 4 of connector and (-) terminal on pin 3.

My pump draws about 5 amps, for reference.

Hey Savannah, just wanna say I really appreciate your help on this. Im so frustrated right now.

I may have jumped the wrong neg tab on the pump, so I will re-test that tomorrow.

I just checked the inertia switch wires.

The wire on the washer bottle side is 8v key off, and 5.2 key on, staying at 5.2 after what I assume is the fuel relay clicks off.

The wire on the engine side goes up up up with key off. Goes to 12.2 with key on, then goes up up up after relay clicks off.

I just remembered that after I backed out of the garage and shutting it off, I put the headliner back on. I know the wire harness runs up there, but I cant imagine something happened. After jumping the pump again tomorrow Ill take the headliner down and check it out.

Check the grounds on the D-pillar while you're under there. They run to the ECU and may be the issue. I know on the tray back the truck wont start without them connected so they are temporarily screwed to the floor. Not sure what it cuts off but the truck will crank and not start - but if it does start it will die quickly.

The first time I tried to restart, it fired, then died almost immediately. I think that was just residual fuel from backing it out of the garage. It may have happened one other time I tried to start it, but Im not sure.

Does the fuel pump run with key on if those arent grounded?

honestly I am not sure but I can check for you tomorrow

Ok, thanks. I believe the ETM says that ground on the back drivers side pillar is straight shot to the pump connector. I just went and checked it out and it looks fine.

re:
The wire on the washer bottle side is 8v key off, and 5.2 key on, staying at 5.2 after what I assume is the fuel relay clicks off.

The wire on the engine side goes up up up with key off. Goes to 12.2 with key on, then goes up up up after relay clicks off.

When you are making the above readings, where is black wire from meter?

What scale are you using on the meter (volts, ohms, amps, etc.)?

Unplug connector from inertia switch. With truck off, read for ohms (continuity). Short meter probes together, meter reading shoud change. Now put one probe on negative battery post. Put other on each pin of the inertia switch cable you unplugged. One pin should have a reading, because it would see continuity from the connector to the fuel pump and back thru the ground return path. Other pins should have no readings on continuity to ground. Should be a low ohms reading, like when you read a speaker coil, etc., like less than 10 ohms. If higher reading check connectors at pump, cables, etc.

Those readings were done with black on neg battery and red on an inertia wire. Meter was on DCV.

I will do this first thing I get home from work.