BMW E46 and E83 IHKA Blower Regulator Failure
This Technical Service Bulletin is regarding A/C Blower Motor/Regulator Malfunctions in BMW E46 3-Series and E83 X3 vehicles. The vehicle seems to have a faulty blower regulator right after the A/C control panel is replaced. The disconnect of the 18 pin connector from the A/C control panel within 15 minutes after turning the engine off (run-on period) will send a voltage spike to the blower regulator temporarily disabling it.
In this situation the blower regulator will will not necessary have to be replaced. It can be reactivated by pulling the fuse 50 which resets the blower motor. If resetting the blower motor does not reactivate the regulator, the part will have to be replaced. BMW does currently not allow the use of the blower regulator 64.11.6.923.204 which used to be made by Sitronic and distributed by Valeo, but recommends to use the latest version of the regulator. To avoid this problem in the future disconnect the terminal 30. This will prevent voltage spikes in the blower regulator when disconnecting the A/C control panel.