Instrument cluster lights turn off when map light is turned on

[dkad260]

2012 Denali

When I press this overhead map light button...

My cluster lights turn off.

Currently, the map light button will not turn on the map lights, but the interior dimmer switch will.

This just happened out of the blue, no other symptoms or issues.

Only thing I have done, was install some VLeds headlights and fog lights a couple months ago.

Edit to add: If I turn on the map lights with the dimmer switch, I can turn off tbe map light with the button...very odd.

Thoughts?

 

[mikez71]

Both power sources to the dome lights come from the BCM.

If none of the other dome lights do the same thing.. possible bad switch?

I had some dome lights that were LED, and when the BCM went to sleep, the light didn't draw enough current to waken the BCM.
When I manually activated them, they flickered very faintly.
Once I keyed on or did anything to wake the BCM, they would light up with the switch normally.

 

[dkad260]

If none of the other dome lights do the same thing.. possible bad switch?

This is for both of the front seat map lights...for the driver and passenger. Either switch will turn off the instrument cluster light. No LED's inside.

 

[mikez71]

How about rear passenger dome lights?

 

[dkad260]

How about rear passenger dome lights?

When I turn on the second row map lights it does the same thing.

 

[mikez71]

How about when you open your sun visor?
Because that is on the same circuit as the reading/map light power. (orange wire circuit 6815)

Interior Lights Schematics 1 — 2012 GMC Yukon Denali AWD V8-6.2L Service Manual | Operation CHARM

Detailed repair manual for the 2012 GMC Yukon Denali AWD V8-6.2L.

charm.li

Looks like there is a connection at the left I/P junction block.. Sometimes there can be corrosion on those connectors.

I can't figure out why your dash dims at the same time.. makes me wonder if it's a BCM or dimmer switch issue.

 

[dkad260]

How about when you open your sun visor

The driver's side light is burned out, but when I open up the mirror on the passenger side it does the same thing.... instrument cluster lights dim.

 

[mikez71]

Might unplug headlight switch just to see if it acts different.

Since headlight switch has dimmer and dome defeat, it might be confusing the BCM if bad...

 

[dkad260]

Might unplug headlight switch just to see if it acts different.

Since headlight switch has dimmer and dome defeat, it might be confusing the BCM if bad...

Sorry for not staying on this...but have had alot on the plate recently...but back in the game.

Symptoms of the IC lights are the same, but my parking sensor had been intermittent during this time and I didn't give it much thought. So I went to pull any codes and found this...

May or may not either be a correlation or possibly the causation. Going to take a look at the sensor.

 

[dkad260]

I want to also note around late November I installed some Vled V50 monochrome LED's, in both the headlight and fog light locations. Any chance this could be playing with the BCM?

I removed the #1 parking sensor and no change, I also tried with the headlight switch removed. With the headlight switch removed, the map lights will still not work and I can see a slight load on the IC lights when pressing any one of them.

The map lights will however still light up with the door open, and turn off when pressing the map light with the door open....but won't turn on when door is closed with the press of each map light button.

 

[dkad260]

I did order a new OE headlight/dome light switch... will update once I receive it.

 

[dkad260]

@mikez71 Going to try switching later today, but I also noticed my liftgate wants to open but is struggling after the latch releases...and won't lift under the motor....is this tied to that circuit/module. Starting to look like a possible bad ground...but not sure.

 

[mikez71]

Doubt it. Liftgate module separate from dash lights, grounds at D-pillar...

Trunk, Tailgate, Fuel Door — 2012 GMC Yukon Denali, RWD Service Manual ~ LEMON Manuals

Repair manual for the 2012 GMC Yukon Denali, RWD, including electrical diagrams, bolt torques, and labor times.

lemon-manuals.la

Possible the liftgate struts are weak?

 

[dkad260]

Possible the liftgate struts are weak?

They're maybe a year old, and have no issues holding the liftgate open.

 

[mikez71]

Ok. Well all I can come up with is to check for adequate power and ground to the module. If those are good, maybe it's a failing motor or liftgate module?

Here's another diagram for the dome lamps.. wired straight to BCM..(orange and gray wires)

Interior Lights — 2012 GMC Yukon Denali, RWD Service Manual ~ LEMON Manuals

Repair manual for the 2012 GMC Yukon Denali, RWD, including electrical diagrams, bolt torques, and labor times.

lemon-manuals.la

 

[dkad260]

Thank you for the diagram.

Well, ..lol...it's been a long week, have a ton of projects going on and I failed to check something. I had the interior overhead switch for the liftgate in the OFF position.....

 

[dkad260]

Replaced light switch, no change. Will look into the diagram.

 

[mikez71]

Starting to wonder if BCM is bad...

 

[dkad260]

Deleted this post as my info was wrong, forgot the daylight sensor was still seeing daylight.

 

[dkad260]

Starting to wonder if BCM is bad...

I agree it's looking like a possible BCM. I'll get under there again and do some checking. I'm going to order a new OE BCM to be on the safe side while they are still avail from GM, as I plan on keeping this vehicle for awhile. I don't like to blindly throw $$ at something before I do the diagnosing...but what's here today could be gone tomorrow without warning from GM.

The steering wheel lights make it more confusing as I would assume all the lights feed from one power source.