Conversation Between subford and jhutchison40

The red wire from the PCM Power relay powers the PCM (EEC) pin 37 which powers EEC, injectors and the fuel pump relays coil.
You need to make sure the Power Relay is closing when the key is in the run or start position. You should here it click when the key is turned.
If it is closing then you are not getting power to common contact fuse "I".





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Okay, so I used a jump box to check everything out, and I'm losing 9 volts from pin 37 which powers EEC, injectors, etc. Is there any way I can wire from the battery to fuel pump relay directly? The truck sat for awhile, and I'm wondering if something got in there and chewed up some important wires.

The power for the contacts of the fuel pump relay (green bottom relay) comes from the fuse link at the starter relay on the passenger fender.
The power for the coil of the fuel pump relay comes from a contact on the EEC power relay (brown bottom relay).
The fuel pump relay coil is grounded by the EEC Computer to turn on the fuel pumps.

Hey Subford,

I have an '89 F150 with a 5.0, dual tank system, I'm wondering what I need to check because I'm not getting any power to the fuel pump relay. I replaced the front tank and fuel pump as well as the inline pump, but when I turn the key to start it, nothing happens. Could you help me out?