I had to pull the interior AC unit to fix the switch which decided I only needed the low and medium speeds out of t he blower motor. While I was in there I decided to replace the wimpy blower motor I was using. When I last had the system apart, during the restoration, I replaced the original blower motor with the Grainger 197 motor I had laying around. The air output was pretty much the same, but I figured leave it there, it’s new.
This time I bought new motor from Carquest/Advance Auto Parts. It’s a Four Season’s motor, made in Canada, part number 35576. Very quiet, no noise when running at no load at full speed. Size is a bit over 3" long and 3" in diameter, shaft is 1/4" and already “D” shaped. Installed in the AC unit it moves significantly more air; I’d estimate at least 50% more. Cost was about $28.
It would also be a better substitute for the heater blower motor, especially for those who don’t want to cut up their heater fan box.
I haven’t had much luck repairing the fan switch, the plastic parts in mine are iffy. So I bought an electronic variable speed controller rated at 20 amps maximum, more than enough to handle the fan motor. I’ve installed it with a relay so it’s powered only when the factory AC switch is turned to one of the three blower positions and triggers the relay. So, now I have an infinite number of AC fan speeds and hopefully a switch that will last for years and years.