Auto-Dim Issue

Hey all, I have a 2018 dbl cab and within the past few weeks I have noticed that the rear view mirror is not dimming. The power light is still on and if I hold my hand over the sensor on the back it will slowly dim. Anyone else have this issue?

 

Do you have tint on the back window? If so, how dark is it? Do you have dirt/filth/film on that window also? Make sure the glass is thoroughly cleaned. It may be that the unit itself is going bad and might need to be replaced.

You can never find "just" the sensor. Usually you gotta buy the entire unit.

 

Thanks for the response. Noting with my truck has changed recently. The window is a tiny bit dirty, but I wouldn't think it would be enough to affect the mirror. Probably going bad.

 

The rearview mirror should darken when exposed to bright headlights approaching from the rear, with the goal being to reduce the reflection onto your face. It should not darken when shielded by your hand, assuming the sensor you refer to actually controls the darkening of the mirror.

 

You are correct...sorta...The dimming feature is based on the amount of light in both directions. The darker it is in front of you the darker your rear view will be. The sensor I am referring to is located behind (windshield side) of the mirror.

 

It sounds like the mirror is fine. The foward facing sensor detects daylight, while the rear sensor detects headlights behind you. If the forward sensor does not detect much light (telling the rearview mirror that it's night) and the rear sensor detects enough light (signifying that a car behind you is pissed off) then it will dim. You covering the sensor in the daytime (I assume) and it dimming sounds like both sensors are working as they should. Also, just to be clear, it doesn't always dim at night, it needs to detect light from behind you.

 

No, I am covering it at night. Its weird.

 

Hmmn

Couple links to help:
Installation
Auto-Dimming Troubleshooting Guide