Lumbar Switch
WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
Battery positive voltage is supplied at all times to the driver and front passenger seat lumbar switches from the MSM LOGIC/RF MASSAGE Fuse located in the rear fuse block. When the lumbar switches are pressed they send a 12-volt signal to the memory seat module (MSM). The MSM then commands the lumbar motors to move in response to the switch signals.