Volvo Repair: 93 850 Volvo, power stage, dash panel

Question
My a/c is not working right.  When I start the engine and with the switch in the off position, the blower blows for about 2 or 3 seconds and stops.  After that when I switch it back on, it does not blow at all.

The a/c switch works because I can here the system cycle on and off.  If I am traveling on the interstate I get the fresh air blowing through it so it keeps me cool that way.

Could this be a control problem or a resistor problem?  If so, can you describe how to fix?  Do I need any special tools?

Answer
Hello Jay,  Your 850 needs what is called the 'power stage',it regulates fan speed. The part runs about $65. and installation is easy. Remove the pass.sd. under dash panel,then match up your part,two screws and its out.Thank you and good hunting!  PKD