Mechanics

03 F150 HERITAGE, NO POWER AT FUEL PUMP.

2003 Ford F-150 • 150 miles

Hi guys, Ive got an 03 Ford f150 Heritage truck V6, no power at fuel pump, checked all relays and fuses also, checked the inertia switch on ride side kicker panel was told needed voltage on both sides, no power there either, the old pump was bad, I bench tested it bad, , bought a new one, but cant get power to it, any ideas? Thanks.
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Pearlhickory
July 23, 2012.



Check the inertia switch for power key for only 2 seconds. Power will return cranking.

If not, back up to the relay and check for power at 2 terminals. The pcm grounds the relay.

If no power, possible ignition switch or fuse.

Roy

ASEMaster6371
Jul 23, 2012.
Going to check right now, wasnt aware of the 2 sec window on inertia switch, I only found power at one terminal on relay, first time I checked.

Tiny
Pearlhickory
Jul 23, 2012.
Just checked the inertia switch, within 2 sec window and crank, no power going to recheck all my fuses and relays, You mentioned power on two terminals at relay?

Tiny
Pearlhickory
Jul 23, 2012.
It look s like there are 2 fuses for the relay

Roy

ASEMaster6371
Jul 23, 2012.
I checked the 2 fuses and 1 relay all have power I understood im suppose to have power for two secs upon ignition ON at relay terminal 87open circ to 87close circ when grounding? NO power at inertia switch on two second ignition key on on test.

Tiny
Pearlhickory
Jul 23, 2012.
If you can energise the relay, see if it powers the pump.

Roy

ASEMaster6371
Jul 23, 2012.
About to check that, let me see if I can energize the relay, what about the inertia switch, and doesnt the ignition switch send power to pump also?

Tiny
Pearlhickory
Jul 23, 2012.
Yep but you need power to the switch before it can send power anywhere

ASEMaster6371
Jul 23, 2012.
I jumped off term 86 to 85 with pigtail, I did get 12 volt to pump plug, but unable to shut off voltage with key at pump plug, did have continuity to ground on black line, and constant 11.5 volts on yellow lead at pump plug, inertia switch jumped out also, .

Tiny
Pearlhickory
Jul 23, 2012.
I wish you had a scan tool as you could energise the fuel pump relay from the scanner to verify control circuits before condemning the pcm

Roy

ASEMaster6371
Jul 23, 2012.
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