Reminds me of the repair bill for $300 for the hammer trick. Asked for an itemized bill. Came back as $50 for the field trip/service call, $250 for knowing where to hit it with the hammer.
My first auto mechanic job was back in 1973, worked for full blooded Cherokee indian (Human one, not a JEEP, LOL!). He was making $200 for a guarteened fix on brand new wiring harnesses for 1973 Oldmobiles that were shorting to ground and blowing the main fuse and frying the harnessess everytime some hit a road bump and latered used the electric door locks or windows.
His fix was beat down the sharp edge that was cutting through the harness (which was also a bit short, adding to the problem) with sledge hammer! Worked every time!!! LOL.
Your hammer trick is probably resseting well worn DC carbon brushes on the armature, if I had to hazzard a quess. Next time you might try replacing those brushes.
I am having window problems too, but mine seems to be a volatge, current problem, or a severe need for greasing the moving the parts.
Thinking about this thread this morning has me now wondering if might not be a poor ground problem?????? on mine (and maybe others!!!!!). I already know I have a volatge meter drop in the dash area when I turn on the ventilation blower motor to high, that is not a real under the hood voltage problem. In fact the windows only partly work, at a terribly slow rate when the blower and headlights are off!!!!!