Door ajar

1998 mercury sable wagon… y does my door ajar warning light illuminate from time to time?

Comes on and then goes off? Since the warning light has your eyes attention, you might not be noticing that certain interior lights are also coming on. Just a thought. Either way, check/oil/manipulate all of the door switches and inspect the surface they touch when doors are shut. A deer hit my passenger door. The only damage was a door that was sprung a tiny bit, but enough to cause this problem. Are you getting this when you hit a slight bump? I corrected mine by layering pieces of mettalic foil tape on the spot where the door switch hits to make sure I got a solid off position.

Look at the door switch and the wires to it.  Likely that is your problem.

This vehicle has no plunger at the jambs. Don’t know where to troubleshoot the problems?

Google…1998 Mercury Sable door switches…and hit…WikiAnswers. Whole bunch of
discussion on your problem. Why do they design problems in? Like a simple switch
has a better solution?

It’s designed that way due to the design of the keyless entry system and how the interior lights come on when the outside handle is lifted (on some option packages). Not that it is one of Ford’s better ideas…

The fix is easy. I’ve done dozens of them. Spray some WD-40 into the area of the latch in the door. That’s where the switch is. It’s PROBABLY your driver’s door as it gets the most wear and tear, but that’s not guaranteed. Then actuate the switch by holding the outside door latch in the open position while clicking the latch open and closed with a screwdriver SEVERAL times. You will probably want to do it to all five doors, just in case.

If your dome light has not worked in some time, it’s probably because someone has removed the bulb or the fuse for that circuit so that the battery won’t run down.

Same problem with a 98 Windstar, same solution too. I prefer CRC Electrical Contact Cleaner to WD-40, but have used both. Spray it into the door latch while working the door handle to clean the switch contacts.

Ed B.

Yes the CRC product is probably better, but most everyone has a can of WD-40 sitting around. If the OP has neither, then he can buy either.

Soak the door latch with a can of PB Blast and work it 30-40 times. Common problem on these cars. Do not use WD 40, IT WILL GUM UP…