Isn't Final Stage Resistor part of the AC system? I think you can tear the AC apart and still can drive (sans the leaks!!) Lets see what the other folks will say, but I'd say - yes, you can drive without the FSR

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E53 X5 4.6iS
147K mi - Sold May 2013
Tireprints left in:
USA, Nicaragua, Costa Rica, Panama, Russia

E53 X5 4.8iS built 2005-10-17
66200 mi - June 2012
96000 mi - June 2013
112000 mi - June 2014
OEM fire extinguisher
OE first aid kit
OE tow hitch
OE TV module
OE aspheric mirror
K&N air filter
black/white badges
rear camera
4-channel video recorder

Here is the list of things I have done to the X