I have a 98 Honda Accord that has a problem like many other people have posted. The dash and A/c lights turn off when the headlighs are turned on. It happened after I installed an after market stereo. After checking every fuse, wiring, and relays I could think of I found this forum.

The only solution that seemed to make sense is replacing the BCM (Body control unit) or multiplexer unit. This device(s) is supposed to be on the driver's side fuse box, but what exactly are these things. Doing a search for either of these items on google doesn't yield any good results.

Any ideas, part numbers, etc would be greatly appreciated.

 

http://www.hondaautomotiveparts.com/...IT+%28CABIN%29

at hondaautomotiveparts.com it's part #210437
after you select your car specs, go control unit (cabin) ->system unit #11

 

And let there be light!!

I finally have light on my dash after an year of checking fuses and wiring. It is an expensive piece of equipment, but at least I can see how fast I'm going at night now.

I found out that the honda dealer know them as both Multiplex contol unit and system unit. The box greatly differs from each honda model. If anybody is purchasing one, I suggest giving the dealer your VIN Vehicle Identification number and specify that it is the driver's side, since there is one on the driver's and passenger side.

The piece of equipment is a white plastic box that is about 3" x 3".

Thanks mycargov6room for the information you gave me.