Ford Door Switches Failing, Easy Fix

In our Ask a Mechanic forums, user kamartin had an issue with a 2003 Ford Explorer XLT:

On my wife's 2003 Ford Explorer XLT, the interior dome light stays on when the door is opened. I think it is the switch in the driver's door. How do I go about replacing the switch to make the lights turn off and not run down the battery?

This is actually a problem endemic to many Ford models from cars to SUVs to trucks. The door switches Ford uses are similar throughout many of the vehicles in its model lines, though this problem seems to surface on trucks and SUVs more often than on cars, likely due to the conditions under which they're often driven.

Kamartin should be looking at something else before replacing switches. His SUV has five doors, so the problem could theoretically be in any of those five doors, if it's not an electrical fault elsewhere.

Luckily, there is an easy fix that Ford owners have known about for years. Nearly every time this happens, it's because the door switch attached to the latch is "sticking" and not moving in and out properly, triggering the circuit that shuts the dome light on and off (among other things).

To fix it, simply clean out the door latch and switch with spray-in cleaner, let the cleaner settle in, then work the door a few times and see if the problem has gone. Cleaner will free up the door switch and allow it to operate again.

While WD-40 is often the spray of choice, it's not a good idea. The switches are electrical and WD-40 is both corrosive and conductive, so there is a possibility it could cause some problems. It's best to use electrical contact cleaner, which is neither corrosive nor conductive.

Simply spray each latch (as pictured) thoroughly, let it settle for a minute or two, then open and close the door several times to exercise the switch and let the cleaner get inside the plunger to do its work.

In most cases, this fixes the problem of an always-on dome light and on some models, the continual "door ajar" light on the dash.