Where's the Sensor ?

[Stoneface]

Where is the sensor that activates the automatic headlamps? The obvious answer is "the little black dome in the middle/top of the dash". But here's my problem with that answer; I can totally cover the dome with a towel or anything & it has no effect on my headlamps coming on. So there is either another sensor for the headlamps or my little dome isn't working as it should. Btw, my headlamps come on/off as they should, I just want to know where's the sensor. Thanks.
Truck is 2013 1500 Limited

 

[mjd91]

In the back of the rear-view mirror.
The one in the little black box is for the auto wipers.

 

[Gill]

In the back of the rear-view mirror.
The one in the little black box is for the auto wipers.

I'm pretty sure the dome on the dash is for the auto-lights and the sensor built into the back of the rear view mirror windshield mount is for the wipers.

Strange how you could cover the sensor and there is no response. Wonder if there is a second sensor or if there is some delay from bright daylight to sudden darkness before the sensor detects the change and activates the lights. Or maybe there is a second sensor?

 

[mjd91]

Just read my manual about it the other day and asked a buddy that works at the dealership. Mirror is headlights, black box is wipers.
You have to be traveling 20 or 25mph for the auto headlights to operate.

 

[ledhed]

You have to be traveling 20 or 25mph for the auto headlights to operate.

My auto headlights come on when I start my truck and it's dark. If I had to go 20 mph in the dark, it would be kind of dangerous.

 

[mjd91]

Sorry, not auto headlights, auto highbeams.

 

[Stoneface]

Yea, I don't think the 20mph theory makes sense, but thanks for the ideal.
Perhaps the answer is the rear view mirror sensor,.... maybe not ?

 

[mjd91]

My mistake. I thought you were talking about the auto highbeam feature. Not the auto setting of headlights.