When I bought my truck I had to replace most of the lights other than the headlights. I mean all the lights, like the cab overhead lights, license plate lights, etc... Anyway, I replaced the bulbs in the courtesy door markers (the white/red light in the door which is supposed to come on when the door is opened). I immediately noticed they stay on all the time now if the ignition is on, regardless if the doors are open.

I also replaced the lights in the third brake light (exterior light above the bed on the cab) and the two white lights on either side of the brake light stay on too! I figured it was a bad door jamb sensor and pulled all of them to inspect their condition. One of the units was badly corroded and fell to pieces. The others looked to be fine, but I disconnected them individually to see if the lights when out. They did not. With the units unplugged shouldn't that tell the door is it closed. Honestly the way these things are made I cannot see how they would register the door as being open, because the seem to default to the closed position unless they are really open. Any ideas guys?

 

One idea comes to mind,, make sure the headlight switch is NOT turned all the way to the left.. That will make the interior lights and the cargo lights come on without a door being open...

 

^^^ That's the same thought that came to my mind.

 

Okay, I am an idiot! There is no resistance in the switch when I turn it counterclockwise like other Fords I've had and the dome light does not come on, but that is exactly why the courtesy lights were staying on. Thanks guys for your help, I will spend the rest of the day in humiliation.

 

Haha, it's okay, we've all been there before. Glad to help though.

 

Don't be too hard on yourself. Welcome to the club. When I bought my 93 4X4 the PO had disconnected the chimer. I left the headlights on 3 times before I went to the junk yard and got one.

I once drove my 02 Ranger gently over to the mechanic's because I couldn't get the brake system bled. Turns out I had the calipers backwards. The owner of the place who is an outstanding mechanic, said, "Don't worry, we would laugh except that we have all done it at one time or another."

Just keep living and learning.

Hunt4Fun