The sunroof electrical system uses a master/slave configuration utilizing a LIN-Bus based system for communication. The body control module (BCM) is designated as the master, while the sunroof and sunshade control modules are configured as the slaves.

As the system master, the BCM uses the LIN-Bus communication bus to enable or disable sunroof and sunshade operation, communicate vehicle information to each controller, and request sunroof or sunshade movement. The sunroof/sunshade controllers provide system status and diagnostic information to the BCM for diagnostic reporting and operational purposes. The control switches places a different resistor ladder network in the circuit depending on the function selected. The controllers analog to digital switch input reads the resulting voltage range and determines the function

Schematic Reference

Sunroof Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Sunroof Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Sunroof/Sunshade

1. Ignition ON, press the sunshade switch to the open and close positions. The sunshade should open and close when changing between the commanded states.
2. Ignition ON, press the sunroof switch to the open and close positions. The sunroof should open and close when changing between the commanded states.

Ventilation

Ignition ON, press the sunroof ventilation switch to the open and close positions. The sunroof should move up and down when changing between the commanded states.

Note: Because of the accessibility of the switches, perform the switch component testing before beginning the circuit/system testing.

1. Ignition OFF, disconnect the harness connector at the appropriate module.
2. Test for less than 5 Ω between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified value, test the ground circuit for an open/high resistance.

3. Verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, determine if the sunroof or sunshade module is causing the fuse to open. Replace the appropriate module.

4. Ignition ON, verify that a test lamp does not illuminate between the circuit terminal 3, terminal 5 (terminal 6 on the S88 Sunroof Ventilation Switch) and ground.

⇒	If the test lamp does illuminate, test the appropriate circuit for a short to voltage.

5. Ignition OFF, verify that a test lamp does not illuminate between the circuit terminal 3, terminal 5 (terminal 6 on the S88 Sunroof Ventilation Switch) and B+.

⇒	If the test lamp does illuminate, test the appropriate circuit for a short to voltage. If the test lamp does not illuminate, test the appropriate circuit for a open/high resistance.

6. If all circuits test normal, test or replace the appropriate module.

Sunroof/Sunshade Switch - Static Test

1. Ignition OFF, disconnect the harness connector at the appropriate sunroof/sunshade switch.
2. Test for 460-480 k Ω between the switch terminals 1 and 4.

⇒	If not within the specified range, replace the appropriate switch.

3. Test for 230-250 Ω between the signal terminal 1 and the low reference circuit terminal 4 while pressing the open switch.

⇒	If not within the specified range, replace the appropriate switch.

4. Test for 75-95 Ω between the signal terminal 1 and the low reference circuit terminal 4 while pressing the express open switch.

⇒	If not within the specified range, replace the appropriate switch.

5. Test for 410-430 Ω between the signal terminal 1 and the low reference circuit terminal 4 while pressing the close switch.

⇒	If not within the specified range, replace the appropriate switch.

6. Test for 330-350 Ω between the signal terminal 1 and the low reference circuit terminal 4 while pressing the express close switch.

⇒	If not within the specified range, replace the appropriate switch.

Sunroof Ventilation Switch - Static Test

1. Ignition OFF, disconnect the harness connector at the S88 Sunroof Ventilation Switch.
2. Test for 460-480 k Ω between the switch terminals 1 and 4.

⇒	If not within the specified range, replace the S88 Sunroof Ventilation Switch.

3. Test for 230-250 Ω between the signal terminal 1 and the low reference circuit terminal 4 while pressing the open switch.

⇒	If not within the specified range, replace the S88 Sunroof Ventilation Switch.

4. Test for 410-430 Ω between the signal terminal 1 and the low reference circuit terminal 4 while pressing the close switch.

⇒	If not within the specified range, replace the S88 Sunroof Ventilation Switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.