My aux fan runs full speed all the time.

Can somebody tell me which temperature sensor is the one controlling the electric fan on my 87 420sel? Is this a normally closed or normally open switch?

Also, which switch (location) in the ac system turns the fan on if high head pressure is present? Is this NO or NC?

Finally, Relay D is for the aux fan resistor. Where is this resistor, and how does it work?

Thanks in advance.

__________________
Thank You!
Fred
2009 ML350
2004 SL600
2004 SL500
1996 SL600
2002 SLK32
2005 CLK320 cabrio
2003 ML350
1997 C280 Sport