Disable auto-dimming? (ambient light sensor)

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mikez71

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The problem:

When I'm in daytime shade, the dash is dimmed. Takes about 20 seconds after pulling into direct sunlight before the dash finally brightens. Need to bypass dimming so it turns on with headlights only..

Sounds like a simple resistor won't cut it. Anyone have some ideas? I'll eventually pull the sensor to see what happens..
 
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mikez71

mikez71

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According to that link, grounding the sensor wire should keep dash bright.. Looking at out wiring diagrams, it's a white wire that goes to BCM X2(J2?) pin 11. Ground is a white/black wire.

Have it disconnected, don't see any white goop. Sunload sensor wiring is L-BU/BK and GY
Might wire a relay powered by headlight output to connect ambient sensor.. no headlight have it go through 600ohm resistor mentioned in the first post link.
 
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swathdiver

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Do you have a dash mat or something obstructing the sensor? Mine switches pretty quick even with the dash mat around it. The sensors are very reliable but have seen them wear out over the years.
 
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mikez71

mikez71

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No dashmat. Probably should try a new sensor, don't want to add wiring for something like this. I don't notice it that often, relatively minor annoyance, but I am hoping it's one of the last little electrical "fixes" I will make to this truck..

Disconnected sensor and backlighting is daylight bright.(makes sense safety wise) Dimmer circuit will not adjust instrument/radio display backlighting, but still adjusts switch backlighting.
 

Airman68

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Mine seems to be "lazy". Takes a long time once outside to brighten up. Somtimes while driving, it dims the dash lights for no reason. Wonder if I should just change the sensor??
 
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mikez71

mikez71

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Somtimes while driving, it dims the dash lights for no reason.
That's what gets to me. Even if there is a reason (tunnel/trees) I do not want it dimmed in daytime! Still hoping to bypass, but I haven't worked on it lately as I am trying to glue the cracked dash together.. Using lots of JB weld..

BTW what year is yours? I've seen posts about white goo inside the sensor, doesn't look like it's in mine, but maybe I need to take it apart to see it..
 
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Scott in AZ

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My ambient sensor is failed so my headlights are on all the time, and DRL are never on. I’m getting psyched up to remove the dash, paint it with a Pewter refresh, and replace the ambient sensor.

I think if you ground out your sensor, your DRLs won’t work, and you’ll have same problem as I do.

Then the only other electrical gremlin I’ll have is the fuel gage. My level sensor is starting to fail. Fuel Gage measures accurately below 3/4 tank but intermittent goes to “E” empty when full. I’ve heard I need to replace the fuel pump to fix this.
 

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Foggy

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My ambient sensor is failed so my headlights are on all the time, and DRL are never on. I’m getting psyched up to remove the dash, paint it with a Pewter refresh, and replace the ambient sensor.

I think if you ground out your sensor, your DRLs won’t work, and you’ll have same problem as I do.

Then the only other electrical gremlin I’ll have is the fuel gage. My level sensor is starting to fail. Fuel Gage measures accurately below 3/4 tank but intermittent goes to “E” empty when full. I’ve heard I need to replace the fuel pump to fix this.
Try running 2 bottles (big ones) of Techron Fuel System Concentrate in
your next fill up. Might take 2 tries... This is pretty common on the early 2000+
GM stuff. Shit gets built up on the sending unit. Techron will fix it most of the time..
if it does, make sure to run the techron thru regularly (only use the black bottle that says
Concentrate) , the other ones suck
 

Scott in AZ

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Try running 2 bottles (big ones) of Techron Fuel System Concentrate in
your next fill up. Might take 2 tries... This is pretty common on the early 2000+
GM stuff. Shit gets built up on the sending unit. Techron will fix it most of the time..
if it does, make sure to run the techron thru regularly (only use the black bottle that says
Concentrate) , the other ones suck
Foggy if this works Ima’ come correct w you. Thanks already. I’ll give it a try and let you know.
 

Airman68

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That's what gets to me. Even if there is a reason (tunnel/trees) I do not want it dimmed in daytime! Still hoping to bypass, but I haven't worked on it lately as I am trying to glue the cracked dash together.. Using lots of JB weld..

BTW what year is yours? I've seen posts about white goo inside the sensor, doesn't look like it's in mine, but maybe I need to take it apart to see it..
Mine is a 2008. Still trying to work out some bugs and this one bugs me...
 

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