I have 2 door sensors on my 2000 Mountaineer that are not working (at least I'm pretty sure it's only 2). Door ajar light comes on.

Money is tight so I've been searching for info on how to change them out myself but so far I have not found anything that helps. I'm keeping interior lights turned completely off so they won't stay on after I close the doors but I'd really like to get this fixed. I forgot to turn off the interior lights one day, was in and out of the vehicle several times, and it drained my battery far enough that I had to get a jump to start it.

Can anyone help me out with this?