Dimmed Backlit Dash and Radio/HVAC Lights

EddieC · Oct 28, 2024

My 2008 Tahoe backlite dash/instrument/radio/radio lights seem to randomly get very dim and a while later they brighten up to normal without any input on my part. This occurs (randomly??) during the daylight and I don't know what could be causing it or how to fix it.
Any ideas?

Miami-Dade · Oct 29, 2024

@EddieC Moved you here from 15-20 section.

Shubbydog · Oct 29, 2024

Sounds like a failing dimmer switch.

Doubeleive · Oct 29, 2024

could be the switch, should be cheap and easy to replace

EddieC · Oct 29, 2024

Miami-Dade said:
@EddieC Moved you here from 15-20 section.

Thanks, I missed that.

mikez71 · Oct 30, 2024

Shouldn't it be the light sensor/circuit since the dimmer only works at night?

Dim backlight has been bugging me more since I got a dashmat.
The sensor has a resistance of ~600ohms in direct sunlight, and 15,000ohms in full dark. Not sure the exact setpoint, but 10k ohm will put it in dimmer mode IIRC..

I'm planning at least one of 3 things (maybe combo of all...)

1. switch with day/night resistors to manually select brightness (or mode)
2. relay with day/night resistors triggered by the parking/headlights
3. resistor wired in parallel from light sensor input to ground, to de-sensitize light sensor.

Doubeleive · Oct 30, 2024

mikez71 said:
Shouldn't it be the light sensor/circuit since the dimmer only works at night?
Does the dimmer dial work when it's dim?

Dim backlight has been bugging me more since I got a dashmat.
The sensor has a resistance of ~600ohms in direct sunlight, and 15,000ohms in full dark. Not sure the exact setpoint, but 10k will put it in dimmer mode IIRC..

I'm planning at least one of 3 things (maybe combo of all...)

1. switch with day/night resistors to manually select brightness (or mode)
2. relay with day/night resistors triggered by the parking/headlights
3. resistor wired in parallel from light sensor input to ground, to de-sensitize light sensor.

the interior/cluster/door switch/panel lights are on day or night, they just dim at dusk
in any case the switch controls the brightness and headlight switch turns them off to this
the lowest you can get the interior is to this, the ppv's might have a option to turn that off also

mikez71 · Oct 30, 2024

Right, sounds like his go nighttime dim in the day.?
My dimmer only works in nighttime mode..??

FWIW, AutoSync w/BCM option can reprogram dimmer brightness. So full dim can be fully off.

Doubeleive · Oct 30, 2024

mikez71 said:
Right, sounds like his go nighttime dim in the day.?
My dimmer only works in nighttime mode..??

FWIW, AutoSync w/BCM option can reprogram dimmer brightness. So full dim can be fully off.

the dimmer should work anytime, just harder to tell in daylight (try covering the cluster with a piece of cardboard to shade it then adjust the knob to see)
but... I could be wrong this has come up before in the past, I think the issue was not being able to turn off the lights during the daytime because they are always on

Scrappycrow · Oct 30, 2024

The dimmer works in daylight, and it's easiest to tell if you watch the radio screen while turning the knob.

Dimmed Backlit Dash and Radio/HVAC Lights

EddieC

Full Access Member

Miami-Dade

Shubbydog

TYF Newbie

Doubeleive

Wes

EddieC

Full Access Member

mikez71

Full Access Member

Doubeleive

Wes

mikez71

Full Access Member

Doubeleive

Wes

Scrappycrow

Full Access Member

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