EDIT: I looked at my parent's 1998 (not so grand) Caravan this morning. There are 6 wires connected to the brake light
switch. Use a voltmeter to test. A test light
can burn out a sensor line of the car's computer. Pete has a better suggestion below...
I can not answer the ABS part, my "new" tow vehicle is a 1975 IH Scout. The brake switch is usually located up under the dash. Follow the lever arm of your brake pedal assembly up under the dash. There will be a stop that the brake pedal rests against. There should be a switch on the stop. This is the brake switch, it has a small piston that rests against the lever arm. When you depress the pedal, the piston moves out and turns on the brake lights
If the switch has 2 wires, you got lucky. Use a voltmeter or test light
find your connection (Hot when depressed, cold with the pedal resting against the stop)
It the switch has 4 wires, the other 2 wires are for the cruise control.
More than 4 wires? No idea!