DIC Dimmer Switch

[JohnnyR]

The illumination for the instrument panel in my 2005 GMC 2500HD is not very bright anymore. Rolling the dial switch does nothing to change brightness. Just stays at the low setting. Is this switch replaceable and how do I access it?

[Kennedy]

If you are talking about what I think you are talking about this would be part of the headlight switch.

[JohnnyR]

Perhaps it is, but this dial regulates the brightness of the DIC readout showing trip odometers, fuel mileage, etc. as well as it manually turns on the overhead cab lamp when rotated all the way toi the top. Is that all part of the headlight switch or a separate control mechanism?

[DmaxMaverick]

It should be integrated into the HL switch. If you are talking about a switch I've never seen, that isn't next to the HL switch, I dunno. Pull the IP bezel and get a look at what's behind it. You'll probably answer your own questions doing that.

Read the output voltage of the dimmer. If it varies and the IPC doesn't dim, the the IPC is bad (not too uncommon on a 2005). If it doesn't vary (stuck at ~8V, for example), the switch is bad.