MB along with most other manufacturers use a network of zone controllers. Small computers that talk on the network. They interpret and communicate sensor data from sensors close by to other controllers farther away and the drive elements that are also in their zone. An example here would be that the roof module has the inside air temp sensor. It interpretes the temp and sends it over the network to the A/C controller (it does this digitally rather than actually separate wires). Another sensor up there is the radio sensor for the remote control (I think radio rather than infra red).

It of course has the sunroof controls and also has the rain sensor for the intermittant wiper I think.

Unfortunately, after checking the fuse the next step is to communicate with the module and see if it is upset about something.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician