Someone (who shall be nameless) impaled our 406 on the towbar of a vehicle which stopped unexpectedly. The damage seemed superficial but turned out to include a busted fan blade (and goodness knows what else). My question is: can the damaged fan motor be safely disabled (until the repairs can be carried out) by disconnecting the motor on that fan or will this cause problems (through confusing the control system?) I have in mind the following post by Bob minchin some years ago (and I have confirmed that my 406 uses the Bitron controller he describes: If the 406 is anything like the 405 in this respect, the control of the cooling fans is managed by a module known as a Bitron which takes inputs from the Aircon controller and a sensor built into the radiator and then decides whether to switch the fans on either in series or parallel by means of three relays mounted behind the front grill alongside the fans. With a cold engine and air off, the fans should not turn at all. switch on the aircon and fans should run in series ie low speed. If the engine gets hot when aircon is on or off, the fans run in parallel ie fast. If one fan runs and the other does not when in series, it just means one need freeing up /oiling. If one does not run when they are meant to be fast, suspect a relay or motor.