Just replaced similar unit in an '04 model. Takes total replacement of wiper motor/transmission assembly.
Turns out it is fairly common, the "control board" goes bad, it is INSIDE the motor, thus necessating the replacement.
Worst part is getting to wiper arms off the studs. They can be a bugger!
Two screws held mine,, one locating stud, pretty simple.
NAPA had exact replacement, $135, core exchange necessary.
You are totally right about the problem being around so long...they should be able to engineer a much better assembly....oh well....
Back to a 5'er after 4 yrs fulltime.
Pulling with a '14 2500 ram, 6.4 Hemi.
Montana High Country 31RE