I have a 1972 Plymouth duster 340 that I currently have the dash out of. I have the wiring harness out of it and have gone through a lot of things tracing it and matching it up w/ the schematic from the 72 Dodge Dart-Demon Plymouth Valient-Duster wiring diagram Manual. Problem is that I think the guy I bought the car from had put in a harness from a 73. Most things are the same as on the 72 schematic. I have a few things that I had not been able to trace out so I don't know what they are. I have a question about "what this wire goes to". It goes into some sort of relay under the glove box on the car. The plug has a 3 wire terminal.It is a male plug. one wire is brown w/ a hint of 2 yellow stripes on it. That wire is really long and has been cut off. it is on the top right (plug pointing away from me). Top left is blue w/ white stripe. Bottom one is light grey. Plug up from that is a female plug for same pattern of plug below that but it has a place where it cam mount to the dash on it there are only the grey and blue wires and the other one is blank. I move up to the next level and there is anpther male plug w/ grey bottom, blue w/ white stripe upper left and brown w/ more visible yellow stripes on it. these ones on the upper male plug are in the same position as the ones on the lower plug. Can you please advise me as to what to do there? It almost seems that I should be just hooking up the two brown wires but I am not sure. Here are some pics to help me explain this

more pics to help. (The yellow wire goes to the door jamb switch from what I can find out)

more

Can't say for sure, but that connector sure looks like a seat belt interlock connector. One of those deals that energizes a relay to permit the start circuit to operate. My FSM is a '72, so I can't help much there.

I'd trace it back to see if has anything to do with, say, the ground for the neutral safety switch on the trans or if it goes straight to a bulkhead connector for the start relay ground side.

Just a guess...

Good luck.

not interlock conector, thats for 74/75s...

pictured relay and wire are simply a relay to turn on seatbelt buzzer and lights when seatbelts are not fastened and you gear the car.

in other words that relay is like a double switch that just turns on the seatbelt warning signals when NSS ground is lifted ( car geared ) and seatbelt and seat sensors send signal that they are not fastened.

some wiring diagrams are just generic, and doesn't meet all years setups.

on 71 the seatbelts signal was time delay flasher controled ( like the ign courtesy light ) then on 72/73 got this relay and on 74 was changed to the starting interlocked system ( just for USA cars )

Dunno exactly why the looong brown wire is that long but if so, it must arrive to a Tranny ground source somewhere in underdash harness. Normally is bullet kind terminal and close to bulkhead area.

Dunno why not hook it to same brown wire at plug would need to search further on diagrams ( but not mymopar diagrams since that stuff doesn't appears there, more FSM diagrams )


MoparMarq, mostly sure your 72 FSM has this stuff ilustrated

and yes, yellow wire is door jam switch ground


NOTE: IF THE LONG BROWN WIRE GETS SAME GROUND POINT/SIGNAL THAT THE BROWN ON HARNESS PLUG YOU COULD SIMPLY REMOVE THE SMALL HARNES PIGTAIL AND PLUG DIRECTLY THE RELAY TO THE EXISTANT UNDERDASH HARNESS PLUG, GETTING CLOSER ON DASH FRAME THE RELAY TO BE ABLE TO PLUG IT ON EXISTANT LENGHT OF HARNESS. NO NEED FOR CUT AND FIT THE LONG BROWN WIRE INTO THE BLANK SPACE ON MALE PLUG

Relay needs to be chassis grounded

THE SMALL PIGTAIL EXTENSION COULD IT BE DONE FOR MANUAL CARS FOR SOME REASON MAYBE ?... OR BACKWARDS FOR AUTO CARS ? dunno really... would need to check personally the 72/73 A body diagrams. I just have the B bodies and that stuff is ilustrated, but without that pigtail extension.

I'm trying to pull my dash in a 65 Satellite, what's the trick to getting the factory connectors apart without damage??

Good luck on your project, I'll be doing the same as soon as mine is out and on the bench.

thanks

So you think the long brown wire is a ground then?

N eutral
S afety
S witch


Switch located on tranny what sends the ground signal closing the circuit to starter relay just on N or P to be sure won't start up the engine geared.

Same kind of stuff at manual cars but getting the switch mounted on clutch pedal, needing to press the clutch to start up the engine, beinmg sure is ungeared.

This signal was used also on seatbelts system to know when car is geared or not. In that way the seatbelt warning signal is turned on just when car is geared ( so moving ) and seatbelts are not fastened