Installed a 74 rallye dash harness in my 70 challenger and used the factory 70 engine harness. Everything works fine except when the key is turned to ignition it engages the starter. Turning key to start changes nothing it just continues cranking. I can't find a 74 rallye dash wiring diagram...anyone ever experience this? Could it have something to do with the seatbelt interlock (which usually kills the ignition) or could it be the 74 dash harness isn't compatible with 70 engine harness/ ignition switch?

somewhere the blue wire ign1 "run" wire that powers the reg/alt field/upstream side of the ballast is also (improperly) connected to the "I" ignition terminal on the starter relay. sever that connection & holler back if it now cranks/runs normal. EDIT the wire from the "st" terminal on the ign sw should be the only one that runs to/past the bulkhead & on to the "I" terminal on the SR (yellow or yellow with tracer) which is the cranking circuit energizer & it should not "T" anywhere

I noticed that the yellow with tracer coming from the column plugs into the dash harness and the pin it plugs into is a large gauge white wire that runs to the interlock (haven't checked where it goes from there yet) also the seatbelt interlock box is missing and the plugs are just there.

I ain't up on that interlock system but it would control that yellow wire to the "ign" terminal on the SR to keep it from cranking but it is somehow also connected to the blue wire ign1 "Run" wire. I would trace it all out & see where it is bleeding over. EDIT What I would suggest/do now is find the wire coming from the "st" terminal on the ign sw & cut it right where it comes out of the eng half of the bulkhead leaving a short pigtail & splice in a length of wire onto it & run that to the "I" terminal on the SR, removing the wire/terminal that is on there now (just cut/toss that wire back to wherever it comes from). this takes the interlock & the improper connection out of the picture