AHL: Adaptive Headlights: Notes

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NOTE:

A number of control units are involved in the adaptive headlights system (see above: CAS, EGS, SZL).

Depending on the series and model concerned, the adaptive headlights are actuated by the following control units:

> E60, E61, E63, E64, E65, E66 up to 03/2005

The AHL control unit actuates the adaptive headlights.

For safety reasons, the AHL control unit is also responsible for the automatic headlight-range adjustment. This is because: Oncoming traffic must not be dazzled by the adaptive headlights. If a headlight sticks in an unfavourable position, the AHL control unit will attempt to move this headlight down (using the stepper motors in the automatic headlight-range adjustment).

The AHL control unit is connected to the PT-CAN.

NOTE: There is a separate SI Technology bulletin (SBT) for the footwell module. On the E90, the adaptive headlights are controlled by the footwell module (FRM). For further information, please refer to SI Technology (SBT) 61 02 04 (091) "Footwell module".

The AHL control unit is the identical component on all vehicle models with option 524: The AHL control unit is encoded for the model concerned at end of the assembly line.

The AHL control unit is the master control unit for moving the headlights (for automatic headlight-range adjustment and adaptive headlights). The AHL control unit sends the position and the speed of movement to the stepper motor controllers (in the headlight housing). The stepper motor controllers then control the stepper motors for the headlights accordingly.