I went to two auto parts stores to get a EEC relay and no one no one could look up the part. Made a second trip with the old part, but I ended up with the same relay as the fuel relay. This did solve the problem but are these really the same relay. The old EEC was replaced by a shop a year ago or so, did it burn up because they put the wrong one on? Guess if nothing else I now know you can test the EEC with the other relay.

91 f150 300/6

 

A relay is a relay, nothing special about them, they all do the same thing. As long as it plugs in it should work fine. Now there are different ways to wire up relays, but the relay still does that one simple function, turns something on.

 

Relays that share the same connection pins may not share the same operational functions. control circuit could be normally open or closed and the controlled circuit(s) could be cofigured either n/o or n/c. Some relays will simultaneously open a n/c controlled circuit & close a n/o controlled circuit. There are other relays that share the function config. as the ECC(PCM) relay especially in later model trucks, EXCEPT FOR ONE THING eunique to the ECC relay: a resistor built into the control circuit. I don't know if relays are color coded, but all the Ford ECC relays I've seen personally are dark green. Don't remember the spicific function of the resistor(guess-extended longivity) but I'de hate for you to find out the hard way. Depending on the year sources limited to dealer &/or junk yard. What was happening and how was it that relay was determined as the cause. 1 failure, not overtly unusual. Multiple failures imply electrical abnormalities, hi alternater out put, getting or giving jump starts, battery problems? There's my 2 1/2 cents.

 

I will try to check with the dealer and see if there is any difference. I think most relays have resistors but I can't immagine all resistors being the same. As far as the problem, the EEC relay just quit after the truck died once then restarted a few days before. Thanks for the cents