Working on a 99.5 A4 Jetta ALH, Replaced a blown-up AC high/low pressure switch and charged the system. Compressor clutch engages but the fans don't come on. All fuses are good. Checked fans per the beginning of this thread and they work on low and high when jumping at the radiator temp sensor plug. Before I buy a FCU I want to confirm my diagnosis. The FCU is working partially since it turns on the compressor and the high speed fan (when jumpered). Is it likely that one mode of the FCU would fail? I've tried different searches on this thread but haven't found exactly this situation. Thanks for your help.