I believe the fog lamp push button is in the center stack of your dash , below your radio
look for the problem in the ignition switch.
On the console , in front of the armrest
No, the fog lights have a switch.No, the fog lights have a switch.
On the center console near the parking brake handle
( # 20 ) is a 15 amp fuse for the covertible top switch on a 2003 Ford Mustang
On the console in front of the arm rest ( according to the Owner Guide )
The multifunction switch inside the steering column is bad.
How the brake lights work on a 66 Mustang is very simple. Power goes from the headlight switch to the brake light switch, then through the turn signal switch and back to the brake lights. There is no fuse in that system. There is a self resetting circuit breaker in the headlight switch, but, if that was tripped, none of the lights on the car would work. The first thing to check is the brake light switch itself by bypassing it. Unplug the connector from the switch and run a jumper from from one slot in the connector to the other. If the brake lights come on, replace the brake light switch. If they don't, the problem is either a wire has lost continuity or there is a problem in the turn signal switch.
Even after replacing the switch it needs to be aligned with the shifter. Put the car in reverse and then have someone watch the lights as you loosen the switch and then rotate it slightly forward or backwards. once the lights come on, secure it in position.
I would guess the headlight dimmer switch on the floor board is bad or has a loose wire. Possibly the head light switch is bad. The headlight switch has a separate circuit breaker for just the head lights.
The interior lights are controlled by the headlight switch and are protected by a fuse.
If fuse is ok, could be a bad headlight switch