I am working on my sons 2001 Golf GTI 1.8T. I have read and printed out Dan's trouble shooting guide. I am stumped and need more help.
Symptom:
With ignition on and a/c selected with fan control in low, i do not have any radiator fan or compressor clutch.
Items Checked:
Fuses 5, 16, 25, & green fuses on top of battery.
Compressor clutch, applied 12 volts to green/black wire on 10 pin connector at FCM. Applied ground to brown/black wire on FCM. A/C Clutch engages.
Monitored blue/red wire on 10 pin connector (FCM) for 12 volts when A/C Switch is on. Power follows switch position.
Checked Ambient temperature switch at FCM 10 pin connector, bl/ro to gn/bl 700 ohms. Logged into the ECM and it is showing approximately correct temp (86 degrees).
On this car ('01 GTI) the temperature in ECM is NOT the ambient temperature switch. Also, notice it is call a "switch", not a sensor.
Checked high pressure switch connector (by expansion valve) for 12 volts, checked white wire and have 2.3 volts present with system turned on.
4 wire switch or 3 wire sensor?
Applied a short across the radiator thermal switch, I get both low and high fan speeds depending on on contacts shorted.
Operated engine at 3,000 to see if compressor clutch engaged, it did not.
Don't remember the exact cut off RPM, but repair manual usually asks for 1200-2000 RPM during tests. That may have been too high and actually shut AC off.
System has static pressure of 110 on both low and high sides.
At this point I believe I might have a bad FCM module, your help would be very much appreciated.
David L. Jones