My fog lights will not turn on. The green light on the fog light switch turns on, but the lights don't. I changed the fuse, but the lights still don't turn on. Any suggestions ?

check fuse 19 in underhood fuse box. Check for battery voltage coming into the MF switch on the red/light green wire. Then check for battery voltage on the white/yellow when you turn on the fog lamps. Next, check for battery voltage on terminal B16 in the relay socket after pulling the fog lamp relay

a fuse number 24,,,
The following specifications are for the Ford Contour and Mercury Mystique manufactured throughout 1995-2000.
Fuses Rating Color Circuit Engine bay fuse box 1 80 Black Power supply to main fuse box 2 60 Yellow Radiator fan 3 60 Yellow ABS 4 20 Yellow Daytime running lights 5 30 Light green Fog lamp 6 30 Light green Not used 7 30 Light green ABS 8 30 Light green Air pump 9 20 Light bue PCM module 10 20 Light bue Ignition switch 11 3 Violet PCM memory 12 15 Light bue Horn & hazard flasher 13 15 Light bue Oxygen sensor 14 15 Light bue Fuel pump 15 10 Red Right-hand low beam Passenger compartment fuse box 16 10 Red Left-hand low beam 17 10 Red Right-hand high beam 18 10 Red Left-hand high beam 19 7.5 Brown Heated door mirrors 20 10 Black Windshield wipers 21 30 Light green Electric windows 22 7.5 Brown ABS 23 15 Light bue Reverse lights 24 15 Light bue Brake lights 25 20 Yellow Door locks 26 20 Yellow Main light 27 15 Light bue Cigarette lighter 28 30 Light green Power seats 29 30 Light green Heated rear window 30 7.5 Brown Engine management 31 7.5 Brown Instrument pannel lights 32 7.5 Brown Radio 33 7.5 Brown Front and rear sidelights (left) 34 7.5 Brown Interior lighting & clock 35 7.5 Brown Front and rear sidelights (right) 36 30 Light green Air bag 37 30 Light green Heated blower 38 Unused Relays Color Circuit Location Engine bay fuse box R1 Green Daytime running lights (Canada) R2 Black Radiator fan (high speed) R3 Blue AC cut-out R4 Brown AC clutch R5 Dark green Radiator fan (low speed) R6 Yellow Starter R7 Brown Horns R8 Brown Fuel pump R9 White Low beam headlights R10 White High beam headlights R11 Brown PCM power supply Passenger compartment fuse box R12 White Interior and courtesy lights R13 Yellow Heated rear window R14 Yellow Heated blower R15 Green Windshield wiper motor R16 Black Ignition R17 Unused R18 Black One touch window switch Driver's door R19 Blue Cruise control cut-off Central fuse box bracket R20 Unused R21 Unused R22 White Fog lights Interface module bracket R23 Black Turn signals Steering column R24 White Left-hand flasher Door lock module bracket R25 White Right-hand flasher Door lock module bracket R26 Unused Bulbs / Lights Wattage Type Low beam headlamp 55 9006 Halogen High beam headlamp 55 9005 Halogen Parking / Side light 5 2357A Wedge Front turn signal 21 2357A Bayonet Rear turn signal 21 1157 Bayonet Tail light 21 1157 Bayonet Stop light 21 1157 Bayonet High mount stop light 5 2723 Bayonet Fog/Driving light 55 893 Halogen License plate 5 6418 Festoon Reverse light 21 1156 Bayonet Front sidemarker 5 2357A Wedge Glove box Map light 5 64111 Wedge Dome light 10 6411 Feston Step/Courtesy light Trunk/Cargo area Engine compartment 10 89 Wedge Instrument-general Automatic trans indicator

it sounds like you might have a bad headlamp switch .

OK, you need to connect a relay to one of the 'power' wires under the hood that leads to the bulb of the low beams. Then, the fog lights will go on only when they are turned on or off.

Otherwise, you could have a relay that is controlled by a switch that independently operates the relay and thus the fog lights.

Both methods are legal in, Pennsylvania, anyway.

Sometimes hooking up the relay to the fuse box will only turn the fog lights on if the ignition switch is turned on for switched fuse box contacts. And, sometimes, hooking the relay to the fuse box will keep the fog lights on all of the time, as the fuse box may be energized at all times at certain contacts.

Good luck on installing your fog lights, correctly.

The fuse for the fog lights could be in the Fuse Convenience Center under the dash or in the Engine Compartment. It is most likely a fuse, relay, or could be the Fog Light Switch. You need to test each one starting with the Fog Light Switch first,

Most fog lights turn off when you put your brights on. Check their operation in normal mode first, if they turn off when you turn your brights on... this is normal.

To disable this you need the wiring diagram for your car, you will have to cut 1 wire to be able to have all your lights on at the same time.

I just fixed this problem on my wife's PT. It was the switch on the column. Her car has the fog light switch as part of the head light / turn signal switch. The lights stayed on after turning off the ignition and the lights.
You will most likely have to replace the switch.
Unless you are lucky and a skilled mechanic / electrician you may be able to open up and fix the switch like I just did.

It is possibly the light switch that is faulty but before you change this make sure you check all fuses and relative relays