I assume this is a weak wiper motor, but it's always worth getting a second opinion from the forums. Anyone know why my widnsheild wipers seem to move slowly across the window, both up and down, dry or wet? Not uniformly slow every day, but clearly slower than new. Don't think it's voltage related, as I do have a voltage readout thingy and it does it even when voltage is 14.8.

Sugestions?

 

I'm not certain, but if you can lift both wipers to the up-and-locked position, you could run them to verify it's not some kind of friction thing. Otherwise, I suspect you have a bad wiper motor. Second guess is the regulator. Not sure where that is.

 

My thought too, I have replaced wiper blades on my truck, some glide easier than others for sure. OP, have you changed blades recently?

 

I didi this test and yeah the arms move same speed on and off the window, so I'm pretty sure it's the wiper motor. How hard is that swap?

 

This is a bit older truck, but it sure looked pretty easy to me.

 

I recently had this issue with my 2017 F-150 it ended up to be my wiper transmission not the motor the wiper transmission joints are prone to rust an seize up replacement was about $70 from auto zone

Dorman Wiper Transmission 602-182

 

I went ahead and replaced the wiper motor AND linkage (aka transmission) and it wasn't a terrible job. It's possible that just the linkage would have done it, but I didn't want everything apart without parts in hand. I'm slow at everythingk but this only took me 2.5h. Probably 80% of that was taking apart the cowl to access things. Issue solved.
Note the linkage has different versions. On my 2020 the current is JL3Z 17566 F. A-b-c-d-e are all superceded. Bought the parts from the dealer, they seem to be hard to find around here.