Based on 'wipers only work on high' i'd thing the stalk switch assembly could be shot or possibly its connector is loose or corroded.

Replaced mine a few months ago on my 2K XJ. Not that difficult but requires removing the steering column and dash trim panels.
Make sure you disconnect the battery for a good half hour. Don't want the air bag blowing up in your face while monkying around in that area.

One trick, there's a long threaded stud on the upper steering column trim piece which mates and fastens to the lower trim piece. It makes an interference hassle to reassemble.

I just snipped that stud off, called it a day and it was not really that needed as the steering column halves are solid without it with the other trim mounting screws holding the halves secure enough.

 

Update:

It was the wiper motor. Replaced it and everything works now. Thanks for the reply @moparado !

 

Update:
It was the wiper motor. Replaced it and everything works now. Thanks for the reply @moparado !

Great!
I'd make sure everything in the wiper assembly is lubed well preferably with silicon grease or similar.

Based on your description of the problem i wouldn't of guessed the wiper motor.
Just goes to show and i'll keep that in mind.

 

Again great, enjoy your wipers!