like above if the wiring is suspect, give it a look and make sure it's not a problem waiting to happen. as for wiring a new switch in is easy. you will need a new switch and 4 pin relay,
if i remember correctly off the top of my head, power the switch from a fused place in the fuse box and then thru the switch to poll 30 of the relay. out poll 87 of the relay to ground.
run a main line from the battery to poll 85 and out on poll 86 to the positive of the light. ground the light to the jeep.
Never run light or aux stuff direct from the switch as it can't handle the amp draw and will cause you other issues.
i would verify what i said to make sure as it's been awhile.....