Climate control temperature display to dim in daytime?

2003 CHEVROLET TAHOE
255,000 MILES • 5.3L • V8 • 4WD • AUTOMATIC
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RREARL51
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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.
Sep 15, 2025 at 7:42 AM
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STRAILER
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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.
Sep 15, 2025 at 8:19 AM
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RREARL51
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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.
Sep 16, 2025 at 5:54 AM
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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.
Sep 16, 2025 at 9:31 AM
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RREARL51
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Wonder if wiring is problem if i had schematic of plug I could check with ohm meter find the problem if i had specks.
Sep 16, 2025 at 9:35 AM
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STRAILER
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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.
Sep 16, 2025 at 9:54 AM
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RREARL51
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Three wires on large plug black ones all three have continuity.
Sep 16, 2025 at 11:39 AM
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STRAILER
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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.
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Sep 16, 2025 at 12:10 PM
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RREARL51
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I will check tomorrow, thanks.
Sep 16, 2025 at 6:51 PM
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STRAILER
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Sounds good!
Sep 17, 2025 at 8:26 AM
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RREARL51
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Nothing seams to work going to take some where to fix
Sep 24, 2025 at 6:09 AM
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STRAILER
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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 :)
Sep 25, 2025 at 10:08 AM
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