I just put a new heater core in and now the radio and none of the interior lights work. I double checked all the plugs and they all seem fine. Fuses are all good. I can not find good wiring diagrams to see what I could have screwd up that had those things all in common

Oddly enough, my 91 Kota did something similar in '99 when I changed the battery. The underhood lamp, interior domelight, and the radio all quit. Never did figure it out-to this day they still don't work. Bulbs are good, fuses are good. They're on completely seperate circuits, and the other accessories on those circuits work fine.
I have the FSM, and just have never gotten around to fixing the problem.

Kowalski,
yours was probably a fuse.
There are 2 separate fuses for the radio on
my 91 Dak.
One is under the dash and the other is under the
hood. I had the same problem with mine, found out in the owners manual there were more fuses.
Check both fuse boxes and all the fuses.

Look under the hood in the PDC for a 5 amp fuse, I think it is fuse number 2 if I remember right, this is the "M1" feed which is a non switched circuit for memory, interior lights, Power mirrors, etc.
Without fail the most common cause of blowing this fuse when doing a heater core is hitting the glove box light wiring on the dash frame if you left the battery hooked up when undoing that side..If you had the battery unhooked, and that fuse is still blown, That circuit is a Pink wire....start looking for pinched or rubbed thru stuff on that side.

Rick

Thanks! That's good to know. Maybe I'll get it fixed this year