I don't here the fuel pump ever kick on in my 1990 Ford F150, and I tested all of the fuses and they are good. I was thinking the relay for the fuel pump might be bad -- any suggestions?

did you test your inertia switch and its circuit

If you actually have no power to the pump and all the fuses and relays are good check the wires for a short and if that is good replace the ignition switch. If you think the condition is no power to the pump because it doesn't seem to power up remove the pump and apply direct power to it to see if the pump is the problem.

try resetting fuel pump safety switch behind passenger side kick panel .

Gonna do my best to try to explain what I think you are looking for. I am going to assume that you are having fuel problems so I will give you 4 places to look for power supply problems to your fuel pump. 1. Your fuel pump cut off switch is located in the front passenger footwell by the kick panel access cover. 2. The fuel pump fuse is in your power distribution box located in the engine compartment. That fuse is in the # 10 position. If you are looking in the box towards the bottom there are 2 rows off fuses and in between those rows are 2 relays. I hope you understand. The # 10 position is in the 2nd row, you have 2 fuses then 2 relays and from the relays going left to right it will be the 5th one over from the relays. It's a 20 amp fuse. 3. The fuses for the fuel pump relay is in the # 18 position. That fuse is in the same row as the last one but is the first one after the realys going left to right. It is a 15 amp fuse. and finally number 4. The fuel pump relay itself will be the second relay going from the left in that same "row" that I have been telling you about. That's the # 301 position. I hope this helped and good luck.

Did you check the fuel inertia switch ?

From the owners manual pg 155 :
Engine compartment :
Fuse # 10 - Fuel Pump
Fuse # 18 - Fuel injectors

pg 156
Fuel pump relay relay #302
You can swap the fuel pump relay with one of the trailer tow adapter relays to test with.

You can always jumper the normally open contacts in the relay socket ( shown as the red line below ) :

Did you check the fuel inertia switch in the passenger side kick panel ?

The fuel pump is powered :
the fuse to the fuel pump relay.
The fuel pump relay to the fuel inertia switch
The fuel inertia switch to the fuel pump itself.

At the fuel inertia switch in the kick panel, power from the relay is the Dark Green w/ Yellow stripe wire and the pink w/ black stripe wire is the power. from the fuel inertia switch to the fuel pump.

If you jumper the fuel pump relay, you should hear it run. If not pull the fuel pump relay, and check the pins in the relay socket, pin 30 should be the power from the fuse.



If you have power at pin #30, jumper the relay socket as shown with the red line above, and check the dark green w/ yellow stripe wire at the fuel inertia switch for power.
Press the button on the top of the fuel inertia switch, and check for power leaving the fuel inertia switch on the pink w/ black stripe wire.

This is tests good, check for power at the fuel pump, same pink w/ black stripe wire.
Fuel inertia switch info is in the owners manual, If you did not get an owners manual with your truck ( purchased used ), you can download one from Ford :
https://www.fleet.ford.com/maintenance/owners_manuals/default.asp

Have you checked the fuel pump relay?and you know the fuel pump relay cuts off after about 2 seconds when turning the key on?So be sure the test light you are using is attached when turning the key on,it will come on,and then go off in about 2 seconds.The problem maybe the ignition module,or the pick up coil,the pulse the injectors,that deleiver the fuel to the cylinders.

check the relay on the left side under the hood,check the fuel pump shut off switch i think its by the kick panel left side,and fuses

Check fuel pump fuse, remember fuse send power to relay and relay sends power to pump, Check power wires to pump and make sure FUEL PUMP FUSE IS GOOD if not replace and take care of this problem. Good luck and thanks for using FIX YA.

Then the engine fuse may be blown it will be marked ECM I think, the fuel pump and injector circuits are two seperate systems, the fuel pump most likely has a stuck relay.