Volvo Repair: 940 AC, radiator grill, condensor

Question
Answer -
Toby, sounds like the electric fan isnt working when its supposed too.  There are 2 pressostats that control the fan one is slow speed and one is fast speed.  When the A/C is on, the fan should be runnning. Roger

Roger, These 2 'pressostats', is this something I can change, or do I need a new fan?  You said when the A/C is on, the fan should be running.  Mine is not.  It kicks on from time to time, but its not continuously running.  So, in your opinion, the compressor is ok?  I'll be so happy if I can get this figured out.  
Thanks!
Toby
Los Angeles

Answer
Toby, The compressor has nothing to do with it.  If the car is cooling nicely but is overheating then its a cooling system problem not A/C.  The pressostats on on the condensor behind the radiator grill.  There will be 3 of them. I think the Grey one and purple are the fan ones.  I would check the fan be seeing if the blade moves freely or if its a little stiff, then the fan is on the way out.  If you are replacing the fan, replace the relay also which is located down by the battery box.  Roger