Fuel pump fuse keeps blowing

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Fuel pump fuse keeps blowing

July 26, 2011, 02:00:55 PM

My neighbor has a 5.4 01 expedition that the fuse for the fuel pump keeps blowing. Just started happening turn the key and the fuse blows. Any ideas? We changed the pump and filter on reccomendation of a friend of his.

Fuel pump fuse keeps blowing

Reply #1 – July 26, 2011, 03:28:42 PM

sounds like a pinched wire, unplug the pump, and see if it still blows the fuse, if so then check continuity on both wires an make sure only one is showing ground.

Fuel pump fuse keeps blowing

Reply #2 – July 26, 2011, 03:58:47 PM

Is anything else on the circuit with the Fuel Pump?

Fuel pump fuse keeps blowing

Reply #3 – July 26, 2011, 04:49:08 PM

We did un plug the pump still blows the fuse.. Only the pump on that relay and fuse.

Fuel pump fuse keeps blowing

Reply #4 – July 26, 2011, 08:15:27 PM

Swap fuel pump relay with horn or trailer-tow relay (should be the same) in main fuse box under hood. Might be a bum relay.

Fuel pump fuse keeps blowing

Reply #5 – July 26, 2011, 08:55:05 PM

Did that too.. Both did the same. Still blew for bith

Fuel pump fuse keeps blowing

Reply #6 – July 26, 2011, 10:20:19 PM

so it must be a wire problem

Fuel pump fuse keeps blowing

Reply #7 – July 28, 2011, 10:17:59 PM

OK hold on to your hats!!!!! Here is the SCOOP

Fuse10 20A feeds 1059 LB/OG to fuel pump relay pin 30 battery junction box. Leaves the FP relay on 87 238 DG/YE Splice S139 to the inertia switch and the ECM pin 40. then to the inertia switch. Out from inertia switch to 787 PK/ BK to the fuel pump.

Here is what i would do. Remove the FP relay and see if the fuse blows. If it does the wiring from the fuse to the relay is grounded. I doubt this is the problem. Then i would disconnect the ECM and see if the fuse blows. If it does the trouble is further on down the line. If it does not the ECM is the culprit. If the fuse blows with the ECM removed the problem is in the wiring going back to the pump. Then disconnect the inertia switch and see if the fuse blows. If it does the problem is in the wiring going to the ECM or the inertia switch. If disconnecting the inertia switch does not blow the fuse the trouble is from the inertia switch to the pump i doubt that. You can run the pump at the inertia switch by putting battery on 787 PK/Bk going from the inertia switch to the pump with the inertia switch disconnected. Good luck and this issue is involved and not for a novice.

Fuel pump fuse keeps blowing

Reply #8 – July 28, 2011, 11:31:46 PM

have you checked the connectors for the inertia sw and relay.... my vert has a problem of melting those for some reason... I would also start by checking all the connections in the circuit path, then the above from Tom

Fuel pump fuse keeps blowing

Reply #9 – August 03, 2011, 05:13:12 PM

Figured it out... It was a rubbed wire in one of the harnesses under the air filter box...

Fuel pump fuse keeps blowing

Reply #10 – August 04, 2011, 07:56:01 AM

sweet for you!!!!!!!! sometimes those things are a bitch