I have a very common problem with 92 500 SEL: low air volume coming from air blower.

My mechanic has tentatively diagnosed as blower regulator defect. However, his shop will not replace regulator only. The blower motor has been upgraded since and the experience has been that replacing regulator often results in defect recurring in short order.

Difference in price: $225 for regulator; $850 for motor and regulator (plus labor in both cases).

Shop is very reputable.

Any suggestions? I am trying to sell the car, but cannot until I repair the air volume issue.