And you have replaced the relay? Checked the wiring? I think you have replaced the ECM as well, haven't you? (or was that a different thread? Getting old ya know... memory goes first. )

 

I replaced the relay with the horn relay. I have not made it they the entire wire harness yet and I tried a used ecm.

 

Got a bad connection somewhere then. The main connector under the power distribution box is held in by a bolt, it sometimes likes to work loose, and you get all sorts of weird behavior. Start there, check the entire circuit.

 

Ok I will let ya know. ty for the help

 

I checked all connections and everything seems good. For some reason I get power thru the red wire on the trans relay (red going to trans) for about 20 seconds than it goes out every time. If i just turn the key to the on possition than it only lights up as ling as the fuel pump is running, but when I start the truck it stays lit longer. Any idea what tells it to stop sending power to the trans?

 

The trans relay is energized for three seconds when the ignition is first turned on. (about the same length of time the fuel pump runs.) After that, the PCM will disengage both the trans relay, and the ASD relay. (auto-shutdown relay) It won't re-energize them until it sees the engine turning, either via the crank position sensor, or, the cam position sensor.)

Now, if the engine continues to run, then the PCM is obviously seeing the engine turning.... WHY it is shutting off the trans relay is a VERY good question. As I understand it, you have already tried a different relay, with no change in behavior.... so, it HAS to be either wiring, or, a failing PCM.........

I think an interesting test would be to see if the PCM actually IS shutting off the trans relay. Just hook a test light into the circuit, and see what happens.

 

would it be a bad thing if i jump 12v to the red wire going to the trans?

 

Nope. That's what it expects in any event. Make sure there is a fuse in-line somewhere though.

 

Ok I am going to go out there and give it a try I will let you know what happens. Thanks again for all the advise

 

Good luck.