Here are some possible sources for inexpensive replacements I have saved from various threads over the years.
" 1) AM Equipment 402 E. Hazel St Jefferson, OR 97352, (541) 327-1546 the motor is $29 plus $7 shipping.
2)
www.rvdealership.com that sells a repair parts kit made specifically for these units - includes gears.
3) Replacement step motor at AutoZone. It's a Siemens "Window Lift Motor", part number WL43003.
4) Autozone. The brand is "Siemens"
The ID tag lists the following numbers:
59720-20
121899
5) A 1986-1995 Ford Taurus left front window lift motor matched my motor. NAPA part # BK655-1395 $63.99 I ordered my motor from Auto-Zone Manufactured by Dorman part# 742-206. This has a lifetime Warranty and was $49.99. "
Also these guys rebuild the older non-encapsulated circuit boards:
HERE