It should have only a fuse and a switch, no relay. Check ALL of the fuses with a test light.
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
the bulb has fused or broken or the electronics need fixing
Usually means that all doors (including rear hatch) are not closed securely.
What I do is put my headlights on ( low beam ) and pull the headlight control towards me to turn on the fog lights ( push the control in to turn off the fog lights )
back up close to a door or building... press brake pedal... look into mirror to see if lts are lit