The 1974 Plymouth FrankenDuster has a problem. I recently replaced the guage cluster, heater control panel and a few other things. When I tried to start the car, I got nothing. No spin from the key. I could start it by crossing the terminals on the relay though. NO power to the yellow relay wire, so I unwrapped the wiring tape to the bulkhead. Now, If I remember correctly, 1974 was the only year of the dreaded "Federal Seat Belt Interlock" starter system where the car would not start unless the belts were fastened. This added a few things to the wiring and a fender apron mounted relay/reset unit. Next to the fuseblock is a wierd blue box with 2 master wire plugs going into it. The yellow wire from the starter relay runs into the blue box. I tried using another blue box but the car still wont spin from inside. I tried another ignition switch with no change. I was finally able to get it to start and run by JUMPING a yellow 8g wire to a yellow 8g with black tracer right next to it. GREAT, now it runs but the alternator guage shows a discharge. I ran a jumper from the alternator to the + battery terminal and a handheld meter shows its charging, but the dash guage still shows a discharge.
I'll still keep rooting around to see what went wrong and why, but if I turn up nothing, I could make the "dash wiring bypass" by making the alternator jumper wire a permanent change. I'd just like to know what the heck happened.
Am I correct about the seat belt system being a one year only thing? If not, is this blue box found in 1975 and later cars?