14
System Operation
The seat backs are adjusted from the two different locations as follows:
• The switches in the interior light housing receive operating power through the seat back
relay when the ignition is switched on KL 15. The GM controls the operation of the relay
and the switches provide the ground.
• The switches in the “D” pillar receive KL 30 and allow seat back adjustment whenever
the rear tailgate is opened to gain access to the switches.
• The adjustment motors receive power and ground directly from the switches.
MM
General ModuleBackrest RelayBackrest Adjustment
Switch LeftBackrest Adjustment
Switch Right
Backrest Adjustment
Switch LeftBackrest Adjustment
Switch Right KL30
Motor, Backrest Left Motor Backrest Right
28
Drivetrain
The transfer case, driveshafts, final drives and half shafts make up the drivetrain assembly.
The transfer case is always mounted in the same position on the X5. This applies to other
markets and future models that will utilize different transmissions for different engine con-
figurations. With these models, the transmission tail shafts will be modified to match up with
the transfer case.
The rear driveshaft is a two piece unit using a center bearing, while the front drive shaft is
a single piece that is splined to the transfer case and bolted to the front differential.
The breather vents for both differentials and the transfer case are mounted higher up on the
chassis to prevent water from entering if the vehicle is driven off road through water. The
front breather passes up into the engine compartment and is mounted under the left side
ignition coil cover. The rear breather passes along the under side of the body and is mount-
ed behind the left side wheel arch cover. The breather vent for the transfer case is mount-
ed up high in the driveshaft tunnel.
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