1998 Plymouth Voyager • 6 cylinder FWD Automatic • 170,000 miles

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
March 27, 2011.

I only have a '97 service manual but I think the circuitry is the same. The horn circuit, while it can be run by the Body Computer, is on it's own and should work without that computer.

Start by measuring the voltage on the horn relay socket, terminals 30 and 86 while the problem is occurring. If you find 0 volts, measure on fuse 20, a 20 amp under the hood. Also measure the voltage on terminals 30 and 86 on the low and high beam head light relay sockets. All of those points should have 12 volts all the time. If it is missing, suspect a broken connection under, (inside) the fuse box.

Mar 29, 2011.
Caradiodoc, Thanks for your reply. I tried your suggestion, everything checks out ok. But the problem still persists. Looking at the wiring schematic for the horn circuit, it seems the horn switch may be grounded to the instrument panel ground block. Now if I could only find this instrument panel ground block. Do know where it may be, and what it looks like? Its pretty congested under the dash, if I could get an approximate location it would be very helpful. Thanks again

Mar 30, 2011.
As close as I can tell, that ground block is in the center of the dash between the steering column and heater blower. The picture doesn't show whether it's on the firewall or the bar on the bottom of the dash. Based on the presence of the other connectors, my guess is it's on the dash itself.

Mar 30, 2011.