1991 LC Air Won't Blow on 'HIGH'

I think the fan switches are of dubious quality. Over the years I have lost low and medium speeds and will replace it if I lose medium/high and high.
I have seen the same issue in other LCs. This is possibly where your issue is also. There are other possibilitys such as a dirty evaporator core restricting flow or a air divertor/cable problem, but the switch is most likely.
West-Oz.

losing the lower settings usually means that the resistor for the blower switch is bad. You will retain the high settings. Thats an EASY fix. its under the glovebox- 2 screws hold it in, and it has a 4 wire plug that goes into it. $40 at Toyota, $15 at auto stores. I just tried a new one on mine, and it didnt fix the problem with the high settings. I hate to have to take the dash apart to get to the switch, but I guess its my next option.

THANKS

Thanks for the advice. Sorry I could not help you!
West-Oz