AC Resistor wiring

[Hardway]

Ive run in to another snag on installing the new Painless harness into my '72 SWB Chevy. When I was extracting the harness from the cab there were 4 wires going in to the AC box under the dash facing towards the firewall, a med. blue wire, light blue wire, and 2 yellow wires through a sealing type grommet. The original harness was hacked to death so I just left some wiring hanging and cut it, figured I would deal with it later. Well now it is later and according to the AC harness I got from Painless the wiring go to a resistor inside the box. My question is, how deep is the resistor in the box? I can not feel it by sticking my fingers through the hole where the wires come out. Do I have to take the entire AC box apart? Also, the harness has a 3 wire connector with 1 wire for each color as above. If I were to cut the connector off and hard wire it, what do I do with the extra yellow wire that is left? As always everyones assistance is greatly appreciated.