HELP PLEASE!
Ok guys and gals, I have a 2001 F150 Lariat. This summer, after going to the lake and while pulling the boat home, the headlights came on and stay on. Even if the truck is turned off, the headlights stay on. The only way to get them to go off is to disconnect the battery.

I received some advice from an on-line mechanic who suggested checking the switch and the daytime sensor. Both of these seem to check out OK (unless I did something wrong). Even when I disconnect the daytime sensor and switch, the lights stay on.

The information I have seems to indicate a short somewhere, but I can't seem to narrow it down.

It doesn't make sense that when the switch is disconnected, and the daylight sensor is disconnected, that the lights are still on.

Can anybody help me out? I have a hunting trip next week and would really like to figure this out before I leave. Kind of sucks having to park, pop the hood, and unhook the battery everytime I stop.

Thanks,
dawgn4it

 

My first thought would be a relay.
Your switch sends a low voltage signal to the relay, which is simply an electric activated switch, that turns the lights on or off.
If the relay is stuck in the "on" position, the lights would stay on even with the switch in the OFF position.

That's where I'd start.

 

Thanks Skizriz. Now, can you point me in the right direction on where such relay is located? Is it called a "headlight relay"?

dawgn4it

 

Help! We have a 2000 F150 Ford Lariat and the headlights stay on all the time. Actually, they come on and off. They have run the battery down. SO we have replaced the battery, the light switch and now the GEM module under the dash. We have spent over 600 dollars and the lights are still staying on. Does anyone know what else might be the problem?? Thanks