1998 Plymouth Grand Voyager electrical problem

I have a 1998 Plymouth grand voyager with an intermittent electrical problem. The headlights, wipers(front & rear), door locks, dome lights, interior lights, lower instrument cluster (lights, temp. Gauge, tachometer, speedometer, fuel gauge, gear indicator, mileage and trip meter)and horn don't work.
But, the mirrors, windows, heater fan, flasher, turn signals, upper instrument panel (service engine light, oil light, abs light, brake light),
windshield washer sprayer, radio & clock work just fine. I can get the brights to work only when I hold the switch all the way back.
I recently had the clock spring replaced, but the problem still persists. I checked the connection to the instrument cluster and found no signs of a bad connection, no dark spots, cracks, or loose pins. On the wiring diagram it seems that these things that are not working lead back to the instrument panel ground block. If I could find this I'd check it. Can you please tell me where this is located. I would like to rule everything out before condemning the body control module. Am I on the right track? What else should I check? This is starting to drive me nuts, sometimes the car works perfectly fine, and sometimes it does the for mentioned. Please help. Thank you