I have a 2000 F150 and have always had the headlight switch in the auto position but just a couple days ago my headlights seem to be staying on during the day also. Does anyone know where the light sensor is on my truck?

 

Under the little grille on the dash is the sunload sensor on the '10-'03's

Take a test, by shinning a flashlight into the sensor, to see if it turns the headlamps off.
If that is a no go, you can pull up the oval on the dash, and see if something is blocking the autolamps sunload sensor.

This URL shows the oval being pulled up :
http://www.geocities.com/skyjet1/DRL.html

If there is nothing blocking the sunlaod sensor, a bit more problem diagnoses is in order.

 

It can take up to a minute before the lights switch off, but if you have the key OFF, then shine the light on the sensor, THEN turn the key ON, the h/ls should stay off.

 

My thinking, too much over cast, with marginal sunload sensor.
The flash light should tell straight away if that is the case. If not blocked, or something else wrong ???

The owners manual spec's ~20 seconds for the Sunload sensor to activate ( or in this case deactivate ) the autolamps.

 

Thanks guys, I found where the sensor was and put my flashlight up to it and they turned off, stupid me I put my radar detector on the window about 4 inchs above it I guess it was blocking the sensor

 

The best type of repair $0.00

Check it in daylight sometime.