The GM5 module Trunk Release and Dome/Footwell Light
The GM5 module controls other things in addition to the door locks and windows. Two of these other functions are the trunk release and the dome/footwell light (lights that come on when you open a door or unlock the car with the remote). These two functions are not controlled by relays internal to the GM5, but, rather by a solid state driver IC by Infineon. Depending on your GM5 it may be either a BTS726L1 or BTS728L2. This chip is a two channel high side driver with 4A current capability. One channel is for the trunk release and the other for the footwell light.
The trunk release is connected to the GM5 on connector X253 pin 17 (signal name MERHK). The signal comes from the IC, pins 13 & 14.
The dome/footwell lights is connected to the GM5 on connector X253 pin 18 (signal name IB). The signal comes from the IC, pins 17 & 18.
