I've got an '87 F250 with the 300 I-6 engine. There are two relays together under a plastic cover mounted next to the air filter box. One relay is the fuel pump relay. The other is the EEC (computer) relay. I can't figure out which is which. Can somebody help??????

 

Both should have Ford ID numbers on them...the fuel pump relay is marked: E3TB-9345-A1A or A2A or A3A

 

The Black & Green one is the Fuel Pump relay.

 

Thanks for your quick replies.

It looks like I plugged a fuel pump relay into the spot for the EEC relay. I drove over fifty miles that way with everything operating perfectly. I've corrected the mistake, but now I'm wondering if the two relays are the same amd if they can be used interchangeably. Such info could be handy to know in an emergency situation like I was having.

Does anyone know???

 

The parts store lists two different relays. For the EEC they are going to sell you a MR59 or a MR14.

For the fuel pump they are going to sell you a MR12, MR15, or MR17.

They keep talking about socket differences, so there must be some sort of factory change along the way were it plugs in. You better take your old one to the store with you.

 

Today, I had a chance to pull both the EEC and the fuel pump relays and take a look at the base/plug. They have the same plug pattern. The spade connectors on both are sized the same. And from my mistake of putting the fuel pump relay into the EEC relay socket and driving with it that way, I know that one will work in the other. In an emergency, I'll definitely switch them out if it will help.

If anyone has some experience in doing this, let me know. Thanks.

The truck is an '87 F250 with the 300 I-6 engine.