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2015 Sierra Denali 2500 Duramax - Interior Instrument/Control Switch Backlighting Stays On 24/7

CFee

By CFee
in Troubleshooting & Recalls

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CFee New Member

CFee

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For several months now my 2015 Sierra Denali 2500 Duramax batteries go flat after 2-4 days sitting.  I just installed two new GM Gold batteries.  An obvious problem is that the backlighting on various interior controls, including: Red lighting around the headlight switch and drive mode selector; lighting for trailer brake controls; dimmer switch light; lighting for passenger and driver reading light switches, also rear seat reading light switches; and lastly, piano key (aux switches?) switch lighting.  See the attached photo of the drive mode selector and trailer brake controls.  Photo was taken after the truck hadn't been driven for 24 hours - red backlighting and white control illumination should NOT be on. But they and all the others are.

 

What I've done:  

1. Removed all the fuses from the driver side dash panel fuse block: lights stay on.  

2. Disconnected the bulkhead connector from that fuse block: lights go OFF. BUT: after manually turning the headlights on - the backlights ALL go on again, then fade out slowly (like they are supposed to)when I turn off the headlights.

3. Disconnected all the wiring going to the K9 BCM controller (behind the OBD port). Lights stay on.

4. Put the truck in Transport Mode.  Lights stay on. 

5. Took the truck to a large nearby GMC dealer  They charged me $228, replaced a fuse for the Trailer Brake Controller, and told me I needed two new batteries before they could go any further.    (I bought two new batteries at a much lower cost and installed myself.)  I am hesitant to return to that dealer...

 

The truck has only 79,000 miles.  Any suggestions?  

 

IMG_5032.JPG

Edited by CFee
corrected spelling, added tags
  • CFee changed the title to 2015 Sierra Denali 2500 Duramax - Interior Instrument/Control Switch Backlighting Stays On 24/7
  • 2 weeks later...
CFee New Member

CFee

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Justin Newton - Well, at least we're not alone.  I haven't tried anything further yet - I'm in the middle of replacing the engine oil pan gasket right now - but I'm hoping to get this resolved soon!

ilingdecaden New Member

ilingdecaden

Posted
Posted (edited)
On 11/19/2024 at 1:09 AM, CFee said:

For several months now my 2015 Sierra Denali 2500 Duramax batteries go flat after 2-4 days sitting.  I just installed two new GM Gold batteries.  An obvious problem is that the backlighting on various interior controls, including: Red lighting around the headlight switch and drive mode selector; lighting for trailer brake controls; dimmer switch light; lighting for passenger and driver reading light switches, also rear seat reading light switches; and lastly, piano key (aux switches?) switch lighting.  See the attached photo of the drive mode selector and trailer brake controls.  Photo was taken after the truck hadn't been driven for 24 hours - red backlighting and white control illumination should NOT be on. But they and all the others are.

 

What I've done:  

1. Removed all the fuses from the driver side dash panel fuse block: lights stay on.  

2. Disconnected the bulkhead connector from that fuse block: lights go OFF. BUT: after manually turning the headlights on - the backlights ALL go on again, then fade out slowly (like they are supposed to)when I turn off the headlights.

3. Disconnected all the wiring going to the K9 BCM controller (behind the OBD port). Lights stay on.

4. Put the truck in Transport Mode.  Lights stay on. 

5. Took the truck to a large nearby GMC dealer  They charged me $228, replaced a fuse for the Trailer Brake Controller, and told me I needed two new batteries before they could go any further.   The game subway surfers is quite addictive. (I bought two new batteries at a much lower cost and installed myself.)  I am hesitant to return to that dealer...

 

The truck has only 79,000 miles.  Any suggestions?  

 

IMG_5032.JPG

It sounds like you're dealing with a parasitic draw, so I'd suggest doing a parasitic draw test to identify what’s draining the batteries. Check all ground connections for corrosion or looseness, especially around the BCM and fuse blocks. You might also want to have the BCM reprogrammed, as it could be malfunctioning. Lastly, a faulty headlight switch could be sending incorrect signals, so it’s worth checking or replacing that as well.

Edited by ilingdecaden
CFee New Member

CFee

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On 12/5/2024 at 12:50 AM, ilingdecaden said:

It sounds like you're dealing with a parasitic draw, so I'd suggest doing a parasitic draw test to identify what’s draining the batteries. Check all ground connections for corrosion or looseness, especially around the BCM and fuse blocks. You might also want to have the BCM reprogrammed, as it could be malfunctioning. Lastly, a faulty headlight switch could be sending incorrect signals, so it’s worth checking or replacing that as well.

Thank you.  I'm working on this as time allows!

 

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