Lumbar Support Description and Operation (with Memory - A45): Motors

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

The lumbar support system consists of the lumbar horizontal motor. The motor contains a electronic circuit breaker (PTC), which will reset only after voltage has been removed from the motor. The lumbar horizontal motor moves the lumbar support in the forward or rearward directions. The MSM controls the lumbar motor via a half bridge that is connected to a single power rail internal to the module. The MSM connects both lumbar motor outputs on the power rail to a common reference point whenever they are not in operation. This reference point is biased to approximately 2.5 volts. The MSM checks to see if this reference voltage is shorted to ground or battery before enabling any seat or lumbar motor.

Soft stop functions are not used for driver seat motors that are controlled by either a memory or non-memory MSM.