Bob, I don't know if this helps but about 4 years ago, my 07 Ram wipers began slowly exhibiting similar symptoms - wipers slowing down, intermittent levels weren't responding. Ultimately, they just quit working. Not cool when winter was fast approaching!

I initially thought it was either of the two switches. Didn't get as far as testing grounds but I quizzed couple of friends with 07 and 08 Rams, with similar wiper issues, and they replaced their wiper motors. I did the same and they work like new again. $155 my dealer cost for a new motor. Comes complete with the linkage rods.

Tim