On my last X300 both fans ran slow when the ignition was switched on. This due to a Mod done to circumvent problems with the single pressure switch causing problems.
My latest purchase, another X300 (330), doesn't do this. I have traced the fault to a non-operating relay in the fan control module, the relay that should switch on with the ignition. I have ordered another one.
I decided to de-construct the old module to try and determine the cause of the failure.
The relay that works has a coil resistance of 51ohms. The faulty relay has a coil resistance of 669ohms.
As both coils have a resistor paralleled across them, I assume that the working relay value of 51ohms takes into account the resistive values of both the coil and resistor. Until I un-solder a few components I can only assume that the reading I am getting on the faulty relay coil is the reading of the resistor and the coil is open circuit.
Does anyone know the resistance of the coils with the resistors paralleled across them?

UPDATE
An update on my air-con problem. The relay in the Fan control module that initiates the slow running of the fans when the ignition is switched on, was indeed open circuit and the reading I got was purely the value of the resistor.
New one ordered.
Thanks
Bill W.

 

Replaced Fan Relay control module. Now running as it should.