Vehicle is a 76 450slc without climate control. A/C not working. The fan runs constantly at a low speed, even when the the dash switch is off. Noise seems to reduce as the fan speed increases. Or at least it's less annoying.

1) Should it be on all the time?

2) What's wrong?

My mechanic said the dash will have to be removed to R/R. He said it rates as a 22 hour job. It's not worth a major repair to me; at this point it's just a nuisance.

I'm wondering if I can rig the switch on the dash to turn the fan off entirely. Since I get plenty of heat from the engine into the vehicle (summer and winter), I very rarely use the fan even in winter except for defrost. And in summer, opening the windows and sunroof gets me plenty of ventilation, so I don't need the fan.