65 Valiant 170 Still no activity from the ignition key

Your oil light is a clue. You have SEVERAL separate switches inside the housing that "is" the IGN switch, and all these switches are separate circuits

Usable diagrams:

http://www.mymopar.com/downloads/1965/65ValiantBarracudaA.jpg

http://www.mymopar.com/downloads/1965/65ValiantBarracudaB.jpg

Look toward the bottom of diagram A and find the IGN switch

You have B -- RED power TO the switch from the ammeter circuit (battery)

ACC -- BLACK accessory power to the switched acc buss in the fuse box, hot BOTH in "run" and "acc"

S -- YELLOW "start" hot ONLY in start, goes directly to one push on terminal of the start relay

2 -- IGN2 BROWN hot ONLY in start goes directly to the + side of the coil resistor, gives you hot voltage to the ignition system during cranking is the "bypass" circuit, sometimes called IGN2 by Mopar

IG -- DARK BLUE hot ONLY in RUN (NOT hot in start) give you ignition run voltage, sometimes called IGN 1 by Mopar

So yank the switch out of the dash and see if you have joltage in "run" on the DARK BLUE line. This wire supplies power to the oil light, gauges, ign circuit (through the bulkhead) and the regulator/ alternator It is NOT fused.

It is not clear to me, after you jumper the relay it runs?? with the key in the "run" position? IF so, do the gauges work? IF so, the problem with the oil light is right in the cluster, or the sender wire going through the bulkhead connector

Same with the start circuit. CHECK with your meter/ test light at the starter relay, at the YELLOW wire coming out of the bulkhead at the relay. You should get 12V start voltage when turning the key to start. IF not, go back to the switch and check the ST terminal at the switch. If you have it there, you have trouble in the bulkhead connector.

I'd recommend you pull the connector apart and inspect it carefully. We are running into more and more people with connector problems.