Climate control temperature display to dim in daytime?

Tiny
RREARL51
  • MEMBER
  • 2003 CHEVROLET TAHOE
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 255,000 MILES
Temperature display to dim in daytime I have replace unit no different the day night sensor on dashboard is uncovered and working other than can't see numbers in day its working fine and numbers are there if I block light I can see them.
Monday, September 15th, 2025 AT 7:42 AM

11 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
So the normal illumination is handled by the HVAC control unit when the headlights are off. So you said you replaced the HVAC control unit? Does anything else seem to work okay? When you turn the headlights on does the HVAC light up well? Please let me know so I can help you.
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Monday, September 15th, 2025 AT 8:19 AM
Tiny
RREARL51
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  • 7 POSTS
I replaced HVAC because it was doing it too. Also replaced headlight control no help I have tried head lights on and off no different but HVAC control works as it should.
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Tuesday, September 16th, 2025 AT 5:54 AM
Tiny
RREARL51
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Every thing on HVAC control works as it should except display very dim in daytime at night it’s as should be the original did same thing I thought replacing it might fix problem I also checked sensor on dash its not the problem when covered it dims the other buttons on HVAC control its just display in center that’s dim.
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Tuesday, September 16th, 2025 AT 9:31 AM
Tiny
RREARL51
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  • 7 POSTS
Wonder if wiring is problem if I had schematic of plug I could check with ohm meter find the problem if I had specks.
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Tuesday, September 16th, 2025 AT 9:35 AM
Tiny
KEN L
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Okay, lets remove the HVAC controller and remove the electrical connectors. Then test the black wire for a good ground. Let me know, this should be the problem.
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Tuesday, September 16th, 2025 AT 9:54 AM
Tiny
RREARL51
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  • 7 POSTS
Three wires on large plug black ones all three have continuity.
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Tuesday, September 16th, 2025 AT 11:39 AM
Tiny
KEN L
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Sorry, I forgot to ask you to test the brown wire for ground as well. Check out the images (below). Let us know what you find.
Image (Click to make bigger)
Thumb
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Tuesday, September 16th, 2025 AT 12:10 PM
Tiny
RREARL51
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  • 7 POSTS
I will check tomorrow, thanks.
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Tuesday, September 16th, 2025 AT 6:51 PM
Tiny
KEN L
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  • 54,137 POSTS
Sounds good!
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Wednesday, September 17th, 2025 AT 8:26 AM
Tiny
RREARL51
  • MEMBER
  • 7 POSTS
Nothing seams to work going to take some where to fix
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Wednesday, September 24th, 2025 AT 6:09 AM
Tiny
KEN L
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Sometimes another set of eyes on it can help with these kinds of problems. Please let me know what they say :)
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Thursday, September 25th, 2025 AT 10:08 AM

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