What year is the suburban? The low pressure switch on GM models is replaceable. If it's on the drier. I've replaced a few leaking switches. The rear A/C option ones are a PIA to work on.

Which sensor controls auxiliary fan functions? A BMW sensor is different from switches I've done on most domestic vehicles.

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'06 X5 3.0i - bought @143,123 miles (12/26/20)