Fuel Pump Relay Switch Location on a 98 5.0?

King$nake · October 1, 2009

I DID search for this, but I was only able to find the location for the 91-94 Explorer.

Basically my issue is my fuel pump is only working sometimes. When it doesn't work, I can't start my truck at all (just turns over). However if I keep turning my key over (not starting) until I hear my fuel pump kick in, thats the only time I can start my truck. I've done some research on here, and it sounds like it's a fuel pump relay switch.

Thanks

rwenzing · October 1, 2009

There is no part named "Fuel Pump Relay Switch".

Three things to look at are the PCM Power Relay, the Fuel Pump Relay and the Inertia Fuel Shut-Off Switch.

The IFSO switch is supposed to cut fuel in the event of a sharp impact (like an collision) but it can sometimes cause intermittent starting problems or stalling. It is resettable by pushing the plunger. The location is somewhere up under the dash. My 98 Wiring Manual says "near the radio" but the Ford IFSO switch is often found in the front passenger footwell above the top edge of the carpet or behind the passenger side kick panel.

The 2 relays direct power to the fuel pump among other things. They are both located in the Power Distibution Box under the hood.

Your Owner's Manual has a map of the fuses and relays in the Power Ditribution Box - look in the Roadside Emergencies section. Look up Inertia Switch in the index to find out exactly where it is.

If you don't have a paper manual, use the link in my signature to view one online. Click on Glovebox in the menu bar.

King$nake · October 3, 2009

Ok, my there are (3) different items labeled as '#9' in both my Distribution Box and Manual. Can you please confirm if the circled relay in the picture is in fact the Fuel Relay? If it IS the Fuel Relay, I tried pulling it out completely and starting my truck - didn't seem to have an effect on the Fuel Pump working or not. Haven't checked the Inertia Switch yet.

rwenzing said:
There is no part named "Fuel Pump Relay Switch".

Three things to look at are the PCM Power Relay, the Fuel Pump Relay and the Inertia Fuel Shut-Off Switch.

The IFSO switch is supposed to cut fuel in the event of a sharp impact (like an collision) but it can sometimes cause intermittent starting problems or stalling. It is resettable by pushing the plunger. The location is somewhere up under the dash. My 98 Wiring Manual says "near the radio" but the Ford IFSO switch is often found in the front passenger footwell above the top edge of the carpet or behind the passenger side kick panel.

The 2 relays direct power to the fuel pump among other things. They are both located in the Power Distibution Box under the hood.

Your Owner's Manual has a map of the fuses and relays in the Power Ditribution Box - look in the Roadside Emergencies section. Look up Inertia Switch in the index to find out exactly where it is.

If you don't have a paper manual, use the link in my signature to view one online. Click on Glovebox in the menu bar.

Turdle · October 3, 2009

My 98 uses the furthest left of the 4 small ones in a row ( 4th one in from bottom right) as the fuel pump relay

Try swapping it with another. Shade tree troubleshooting yes, but effective. See if the problem moves to another circuit.

Turdle · October 3, 2009

http://www.explorerforum.com/forums/showthread.php?t=180814&highlight=fuse+relay

King$nake · October 3, 2009

Turdle said:
http://www.explorerforum.com/forums/showthread.php?t=180814&highlight=fuse+relay

Awesome! Thanks for that diagram. It's for a 98 Explorer, correct? Is the PDB the same on the 4.0 as the 5.0?

Thanks again man

King$nake · October 3, 2009

Also, is there any way to determine if the Fuel Pump Relay is in fact the culprit without buying a new one? My local Kragen doesn't have one in stock, so Id have to order it. If there is any way to find out if this is the issue or not beforehand that would be great

Thanks

King$nake · October 3, 2009

King$nake said:
Also, is there any way to determine if the Fuel Pump Relay is in fact the culprit without buying a new one? My local Kragen doesn't have one in stock, so Id have to order it. If there is any way to find out if this is the issue or not beforehand that would be great

Thanks

Well I tried taking a Relay from the Horn and using it in the Fuel Pump Relay, didn't seem to help - truck is still not starting. Can't hear the fuel pump working at all now. This really sucks. So Im guessing the Fuel Pump itself has gone bad?

marragtop · October 4, 2009

You should test the PCM power relay also. It that is bad then the fuel pump won't run. Also, don't forget about the inertia switch. Check the connector wire at the bottom of it to make sure it's on tight.

King$nake · October 4, 2009

marragtop said:
You should test the PCM power relay also. It that is bad then the fuel pump won't run. Also, don't forget about the inertia switch. Check the connector wire at the bottom of it to make sure it's on tight.

Ok, so I checked the inertia switch up under the glovebox. I reset it once (pressing the red button) and for some reason my truck started 10-15x in a row after I flipped that switch - but then it started 'not starting' again. I tried hitting the switch again after that but it didn't seem to work a second time. Im still getting an inconsistent fuel pump.

Basically I have to keep turning the key over until I hear the fuel pump work, then I know if I turn it over it will start. For whatever reason Im only hearing the fuel pump come on every 5-10x tries (average).

So maybe it was coincidence that the inertia switch caused it to start working for a short amount of time?

marragtop · October 4, 2009

Check the connection on the bottom of the inertia switch. While you are there, check to see if you are getting power to the inertia switch. If not, then the problem is between the ignition switch and the inertia switch, which could be the FP relay or the PCM relay.

King$nake · October 4, 2009

marragtop said:
Check the connection on the bottom of the inertia switch. While you are there, check to see if you are getting power to the inertia switch. If not, then the problem is between the ignition switch and the inertia switch, which could be the FP relay or the PCM relay.

Ok, what should I look for in the inertia switch? I think I am getting power to it, because when I flip the switch up I cant start my truck at all. Atleast when its on (the switch) I can get the fuel pump to work if I turn the key enough times.

Also, if the problem is a bad fuel pump - how difficult is it to replace?

Thanks man for the help

Harry d. · October 29, 2010

i have somewhat the same problem i hear my fuel pump everytime i turn the key ,but don't start reset the intertia shut off switch and it started for a few days. then started doing the same thing. can someone help me.

purevenom1 · October 29, 2010

Unplug the switch and see if you are getting continuity through it. You can also use a jumper wire to see if that helps or not in the place of the inertia switch. Had a Bronco II that a buddy of mine bought cause the guy couldnt figure why it wasnt starting and already replaced both fuel pumps regulator. Got it here to my house and jumped the inertia switch and he drove it home. Paid 300 for the truck due to the truck not starting. Runs fine still even to this day. Check your local junkyards for the switches and relays.

Harry d. · October 30, 2010

check all the relays the fuel pump cut off switch everything seem to be wroking good even check corel pack. is there anything else that you can think of that would cause it not to start. thanks for your help

Fuel Pump Relay Switch Location on a 98 5.0?

King$nake

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rwenzing

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King$nake

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Turdle

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