Troubleshooting Notes - FHK (Rear Climate Control System)

NOTE: The modified pin assignments in the test instructions must be used for troubleshooting at the operating unit.

^ Troubleshoot with BMW DIAGNOSTIC SYSTEM or equivalent scan tool.
^ Battery charged, U-min = 12V.
^ Fuses belonging to the FHK system must be in working order.
^ For testing, the suitable adapter must be used and the FHK connected such that it is completely operable. Defect codes are stored by the control unit when connectors are disconnected and checked. The defect codes detected before the diagnostic procedure must therefore be printed out before hand.
^ Inputs (E) not stored in the defect code memory of the FHK control unit:
Buttons (matrix circuit), terminal 50, terminal 15, terminal 30, A/C relay activation, diagnostic link RxD
^ Outputs (A) not stored in the defect code memory of the FHK control unit:
LEDs for function lights, blower control voltage, buttons (matrix circuit), diagnostic link TxD.


Substitute values for temperature sensors

Defective component Substitute value
Evaporator sensor 25°C (75°F)

Substitute values for control wheels

Defective component Substitute value
Left temperature control wheel 50 %
Right temperature control wheel 50 %
Air flow control 50 %
Mixing air control 100 %