Stuck

Just put a new booster and Mastercyl on my 70 Challenger 440RT. While I was at it, I masked off the firewall and did some touchup with my airbrush. Put everything back together and now I cant get the starter relay to kick in. When short out across the terminals, it will engage. Now,I did disconnect and reconnect the bulkhead wiring and moved a lot ot stuff back and forth, but I thought I had everythomg reconnected OK. I must have messed something up either under the dash or elsewhere. Can u guys give me a troubleshooting plan to go thru so I can find out what I did. Electrical issues are my downfall, so the simpler the better. I did try a spare relay that I had.....no luck. Battery is good. Thanks and happy
new year

Short answer, I'd bet it's in the bulkhead connector. You do have an FSM, right? Do you have power to everything else, lights, radio, heater, etc? If so you have power to the ignition switch. Look on the wiring diagram and see if you have power to the starting conductor on the ignition switch when you turn the key to start. This would be on the passenger compartment side. If you do, the switch is good and the wiring to and from the switch is good. Then go to the engine compartment and see if you have power on the same lead when you turn the key to start. My bet is you won't but that is only a bet at this point.

Forgot to ask, manual or automatic? If automatic you could have a problem with the neutral safety switch wiring and have the ignition switch side of it all perfectly functional.

Try bypassing the fusible link. They don't like to be bent or twisted too much at their age.

car is a 4 speed. looked over bulkhead connectors they seem ok. took a test lead from bat pos directly into the fusible link connection on the relay--no luck. also just noticed the headlites not working. everything else has power

Make sure you have the ground terminal on the starter relay grounded. Auto trans grounds through the neutral safety switch the standard trans use a grounded relay or a switch on the clutch.

If you jump the 2 big terminals. You are bypassing the relay and both circuits that feed it. Get a multimeter or test light and check for ground at the small terminal when in Park and Neutral. The other small terminal should be hot when in the start position. Come back with results and we can help you troubleshoot further.

A friend had that problem on 70 cuda, turned out to be starter relay was loose on inner fender and not grounded. Twisted it a little to make contact and it started right up.

I suspect that when you did the touch up with the air brush, you lost a few grounds. Most of the Mopar electrical components ground through the mounting screws, you may have painted right over the grounding process. A good alternative is to run a ground wire under a mounting screw for every electrical "box" that mounts to the sheet metal with screws and connect all the wires to a good ground post. That sure solves a lot of Mopar electrical issues, I've been doing that for years. Gene