Accord Dimmer Control Not Working !

[DjHackStyle]

hey everyone i have a 98 accord LX V6 SEDAN one day all my interior lighting went out, i changed a fuse and everything came back, but my climate control unit in the front actually burned out and my gauges still work but they are VERY VERY DIM, the DIMMER CONTROL on the gauge cluster has also stopped working, i replaced the climate control unit and thats great now, but i replaced the gauge cluster with another one and the dimmer control still does not work, someone told me this might be a multiplex control unit installed in the drivers side fuse box, can anyone determine this for sure ?? my gauges are very dim and the dimmer does not work , any help appreciated, thanx

if it is a multiplex control unit can anyone take a picture of it and show me which one it is?? because everyone said its a blue box and i have nothing like that, in that area only a similar white box.

[jeffcoslacker]

I would just check the dimmer control with an ohmmeter first...

[DjHackStyle]

Originally Posted by jeffcoslacker

I would just check the dimmer control with an ohmmeter first...

the dimmer control is built into the gauge cluster, i replaced the entire unit with a working unit and it doesnt work on my specific vehicle why would i need to tes t the dimmer control ? it works on other cars, just not mine

[jeffcoslacker]

Originally Posted by DjHackStyle

the dimmer control is built into the gauge cluster, i replaced the entire unit with a working unit and it doesnt work on my specific vehicle why would i need to tes t the dimmer control ? it works on other cars, just not mine

You're right, I forgot how it's put together on Accords....my bad.

I wouldn't have thought a '98 would have any multiplexed electrics....seems to me that didn't start becoming common in cars until like '02 or so, but Honda is ahead of the curve on lots of things, so I guess it could be...

I guess I can't offer anything useful here...sorry. I'd just start chasing the illumination wiring from the cluster, and hope to find a problem....check the voltage along the way, try to find the voltage drop...the dim lights are sometimes symptomatic of a broken ground, and a ground breaking could create an arc that would blow a fuse and spike the temp control...i'd almost be afraid for my new control until the problem was found...

Good luck. If you think of anything else that happened around that time, it might help....didn't install anything new or anything, right?

[jeffcoslacker]

Hey! you are right, I found references to multiplex control in '98....it does have it.


I found this about 2000 Accords:

2000 HONDA ACCORD INTERIOR LIGHTING

Recall Date: 06/07/2004

Summary:
ON CERTAIN PASSENGER VEHICLES, THE DIMMER CONTROL FOR THE INSTRUMENT PANEL LIGHTS COULD FAIL DUE TO HEAT BUILDUP.

Consequence:
IF THIS OCCURS, THE INSTRUMENT LIGHTS MAY FAIL AND, AT NIGHT, THE DRIVER MAY NOT BE ABLE TO SEE THE INSTRUMENT PANEL GAUGES, SUCH AS THE SPEEDOMETER.

Remedy:
DEALERS WILL REPLACE A MULTIPLEX CONTROL UNIT FOR THE INSTRUMENT PANEL LIGHTS. OWNER NOTIFICATION BEGAN JUNE 16, 2004. OWNERS SHOULD CONTACT HONDA AT 1-800-999-1009.

Potential Units Affected: 19572

Notes: HONDA ACCORD P36


But it describes a complete failure of the dimmer and no instrument lighting as a result....so the new one should have worked for a short time anyway if this were the case....I'm still leaning towards a ground that broke....that destroys electonics and makes electrics work weakly....

[jeffcoslacker]

The only TSB I could find for the 1998 Accord multiplex control unit dealt with a failure in the remote trunk release mechanism...nothing about dash lighting...

I'll keep looking...

[jeffcoslacker]

OK now I'm a bit confused on Honda's definition of "multiplex"...it appears we are just talking about what everybody else simply calls a body control module...

Anyway. I forgot to ask, does this dimmer adjust the intensity of the radio and temp control lighting also? If so, are they dim also?

[DjHackStyle]

the dimmer controls the intensity of all the interior lighting such as climate control unit and radio, but they are working just fine after i replaced the unit, the only thing dim is the gauge cluster and the dimmer doesn't work......... what do you think

[jeffcoslacker]

OK...so I guess the dimmer control just signals the module, and the module adjusts the voltage to the lighting, not like the old style where the dimmer control was the actual rheostat and the lighting supply voltage ran through it....

So if that's correct, then yes, it sounds like there's either a problem in the MCU, the wiring going to the cluster from it, or the ground to the cluster, if it has a dedicated ground....

That's all I can come up with...not much help...

[DjHackStyle]

so now i need to know exactly where the multiplex control unit is located , a picture would be extremely helpful so i can know what to replace.....