My 1998 Tahoe's windshield wiper system has recently been cutting off unexpectedly. I've only owned the truck for about a month. During one very heavy rainstorm, I pulled over blindly a couple of times and the wipers restarted after I jiggled the arms, only to stop a few minutes later. Does this sound like a switch problem or a motor problem? Of course, they behaved perfectly on the day the truck spent in the shop, so they couldn't diagnose any trouble. I know the wipers spent hours working on that sunny day from the scratches on the windshield. I can tell that the switch has never been replaced after 100,000 miles due to the lettering being worn off of it. Is this a common thing with older Tahoes? Thanks.

Replacing the circuit board module in the motor fixed a similar problem on my '98 Sub.

yup replace the circuit board

Dorman part #906-136 get it at any auto parts store.