On our 2004 we had the same problem and it was something with remote starter it was only 30.00 part and has worked great since!
Usually means that all doors (including rear hatch) are not closed securely.
On a 2002 Mercury Mountaineer : Put your low beam head lights on and pull the headlight selector switch towards you
The first model year of the Mercury Mountaineer sport utility vehicle was 1997 Did you mean 2005 ?
instrument panel or controls?
You can view the Mercury Mountaineer owners manuals online at : www . motorcraft service . com ( no spaces ) Click on Owner Guides ( then select your year , and Mountaineer , etcetera )
a malfunction has been detected ( could be a sensor )
bad switch or possibly stuck switch
The first thing to do is check your fuses. It may be a very simple fix.
If the ((ABS)) Light is on then it's a good thing indicating that the Antilock brakes sensor is in good condition. I too have a 2002 mountaineer
I'm having the same issue as you are. Reshutting...uh...nearly slamming the doors multiple times eventually fixed it. However the problem is back every day and now the rear interior light won't shut off. All the doors are shut and there is nothing blocking them. I'm still searching for an answer. 1997 Mercury Mountaineer 5.0 L could be that the rear hatch may not be closed completely, i have had the same thing happen on my 1998
It is a module under the dash.
the bulb has fused or broken or the electronics need fixing