Interior Lighting

There's a 65 Plymouth service manual which you can download for free over at MyMopar. I know the wiring may be a bit different between 64-65, but they also have aftermarket 2 page diagrams you can download. Look in the wiring section

I just downloaded them, and according to them, the pink power for the dome circuit junctions at the brake light switch, and then goes to the 2nd fuse from the end "where the INST" fuse is. That end fuse is the dash lighting fuse, and if you look on the rear side of the box, has all the orange wires. So you want the one to it. It feeds B2 on the light switch which is the park tail circuit, so if they and the brake lamps are working, the dome circuit should be powered.