BMW Repair: 1981 633csi AC blower, 633csi, rear defroster

Question
I know this car is older than the ones u said u can help with but here goes anyway. My blower 4 the ac and heat quit today, the rear defrost button went out at the same time. I don't know if the 2 are related or not. The fuses seem fine. do u hane any ideas what to check.

Answer
when you say the rear defrost button went out, do you mean it no longer lights up or the rear defroster no longer works? it seems that they may be 2 separate problems. the blower being either a blower resistor or blower motor. does the blower operate only on a couple of speeds or not at all?