3406e ecm will not communicate

I have a 96 379 with a 3406E ser# 5EK70519. Switched the truck off and now it will not start. When I turn on the key the cel and sel lights flicker on and off like a loose connection. sometimes they stay on after a minute or two. when I use my cruise control switch to do a self diagnostic nothing happens. I called a shop to come out and there handheld machine would not communicate with the ecm. I have checked all my fuses and I have taken all my grounds loose and cleaned them. No change.

The wiring schematics I have show a shutdown relay and fuse, but I cannot find it anywhere. I took the connection loose at the ecm and there is 12 volts on #6 pin switched, 12 volts on #4 constant, and ground on #5.

I have tried everything I know to do and am feeling like the ecm is shot.

My question is if I take the ecm off the truck can cat bench test it to see if it is good or not. any other input would also be appreciated

 

called cat and they were very reluctant to bench test the ecm. they wanted me to have the truck towed to them so they could check it out.

I took my ecm and put it on my brother-in-laws truck (which is a 99 with a 1lw 3406e) and it did the same on his truck that it does on mine. so i guess that has narrowed it down to the ecm.

cat wants 2200 for a reman ecm. I found one at a salvage yard off of a 1lw engine for 500. a friend of mine has on off a c-12 that i can buy for 500 also.

will either of these work and will i have to reprogram them for my truck ?

 

got the ecm off the 1lw engine. truck cranks and runs fine. going to test drive tomorrow.

am also going to take it to a local shop to see what hp rating is and to set everything to my liking. (jakes, cruise, and so on)

thanks for all the replies and help.