Just ohm out the switch.
Put a meter on it and go from pin to pin.
Start with a lead on one pin and put the other lead on
another pin... With the switch pushed in, see if you
get continuity. If so, turn the switch off and see if you
have continuity. If it breaks the circuit, you found your
two wires to work the relay. If it doesn't, proceed to the
next wire until you find the two.

One of the wires will also be a ground for the LED or bulb
in the switch, if it's an illuminated switch.

1995 Trooper LS auto 3.2 DOHC /w SOHC intake
1989 Trooper 2.6 auto
1989 I-Mark RS DOHC 1.6
1991 Stylus XS DOHC 1.8