won't start....
Depending on the 904 there are SEVERAL different rooster combs in the transmission.
The wrong one will not ground with the wrong switch in place.
Basically...
If it originally had a 3 pin and you put a 1 pin in it won't work. And visa versa
Easy to test.
Get you DVM put it on diode mode ( makes a tone even the leads are touching each other.)
Hook one to the wire that goes to the starter switch wire and the other to battery negative.
Then run the trans through its positions from park to low
Also get a wiring diagram
mymopar.com free download or
classiccarwiring.com best 25.00 you can spend