Wacky Wipers are a pain, the fix that was recommended was to replace the Wiper pulse control module....

It is a small square box (1998 Blazer) on the face of the wiper motor, 3 Torx screws to remove the face plate...

Part is easily found on the web for around $25.00 plus shipping... I found mine at locally run non-chain parts store...

Good luck

Try 1A Auto.com

Woody, MA

 

Or you could resolder the connections your self for free if you have a soldering iron...