No start, dies after two or three seconds and then no starter engagement

This is a summary of what we have done. First thing we did was to strip back the wiring harness and repair the chaffing over top of transmission cleaned and checked all the external ground points. Removed the dash panel and re- soldered the connectors on the circuit board. We also replace the body module and re-programmed it. (Different problem with the body module) but we thought it may be associated, it was not. We are now at the SKIM module and before we just replace it and have it programmed, I would like to know if there is anything we have missed? I will add that we have checked for loose or corroded connections under the fuse and relay box under the hood. We are not quitters and we will fix the problem no matter what at this point, but maybe someone has had one that all the known cures. I just do not seem to fix it. Everything listed above has been re checked many times by myself and my partner.