My wipers have no intermittent speed. Only on and fast.

Fuse issue?

 

It could be bad motor contacts. I did a diy write to on cleaning them up. Search intermittent wiper fix and you should find it. It fixed my problem. I had sort of intermittent though, like i would put it on intermittent then it would wipe like 5 times in a row, then go off. Idk if yours is just progressed worse or if its another issue. Sounds an awful lot like the motor though.

 

could also be your multifunction switch. That's your directional stick btw.