Hello everyone,
I swapped in a zf5 in place of my e4od in my 1990 crew cab. I rebuilt the 460 in it and also swapped in a dana 50 front axle and bw 1345 transfer case cuz hey why not have a 4x4. I am using the auto ecm because it should allow it to at least start.

problem Im having now is it wont start. starter not moving at all.
things I've done:
1. crossed the wires for the neutral safety switch.
2. checked fuses.
3. bench tested the starter and dont get anything from it then either, tested 2 brand new ones and same story.
4. swapped in a new starter relay. I get 6 volts to the sender wire but it doesnt actually send the 12 volts to the starter side. ( I had all these parts laying around so we arent doing a throw money at it type solution)
5. Only interesting thing it does is when I turn the key it makes the sound for the starter to engage. then all the cab lights cut to half bright and the radio turns off. If I disconnect the battery there is a pop from around the engine relays and when I reconnect the battery the post is hot but everything works again. I checked for grounded wires and nothing.

Any ideas? p.s Lets try to avoid the throw money and parts to solve it.

 

Figured it out. One of the starters tested bad.
the other starter was grounding through the cable.
Anyone who has a similar issue. CHECK YOUR CABLES!!!