passcode or module issue

[Steve_K]

2000 Yukon XL/ 2500. 6.0 engine. Changed out the key cylinder housing which contains the new passcode sensor. This vehicle had cluster mess of wiring from added, then removed security system. So changed out the harness from connetor to ignition switch and Body module. Did the 3 10 minute with 30 second cycle off re-learn process, and exactly same symtoms as before these parts went in.

 

I get a brief start, then engine quits, like fuel relay never engaging. I am wondering if go after the body module next, or if this is wrong direction and I have a separate issue like relay?

 

vehicle has sucked life out of 3 batteries. Keep a kill switch on it 100% of time. This may be hard on these anti-theft devices too.