I have a 2014 320d GT (F34). I believe the HVAC system is the same as an F30/31.
Having problems with the heater/AC blower: sometimes it runs but most of the time doesn't.
It was also randomly switching on when the car was parked overnight causing the battery drain warning message.
Apparently the usual culprit is the FSU (blower resistor unit) which I have replaced with a new one but this has made no difference.
I have removed the blower and verified that the motor is ok; it runs perfectly with 12v applied directly.
It may be that the problem is related to the control unit in the dash (hopefully not ££££) or a faulty sensor of some sort or a wiring fault but I believe there is a relay involved in the circuit and, if so, that is the logical next thing to check.
Does anyone have a wiring diagram for this circuit or can tell me where the relay is located?
Thanks in advance for any advice you can give.
