First off this is controlled by a module (computer) The switch would only have five volts . 5volt reference voltage from the control module . Not knowing how to test the electrical circuit's for this could be expensive . Short out the module or 5 volt ref. voltage circuit inside the module.
Your best bet , take it to a qualified repair shop . Look at a wiring diagram here http://www.bbbind.com/free_tsb.html
Enter vehicle info. year , make , model and engine size . Under system click on body & accessories ,then under subsystem click sun roof . Then click search button then the blue link . Now tell me you under stand what's happening here .
Power Sunroof System Components
The power sunroof system consists of the following components:
• Sunroof control module
• Sunroof Opening Position Switch (SOPS)
• Sunroof switch
• Sunroof motor/actuator
• Sunroof glass (spoiler type, with glass sliding above roof)
• Rail and track assembly upon which the sunroof glass rides
• Power supply for the sunroof control module: SUNROOF 20 A fuse
• Ground from G302
Sunroof Opening Position Switch (SOPS)
The SOPS tracks the position of the glass through 2 limit switches:
• Soft stop limit
• Vent limit
The sunroof control module monitors the limit switches and based on the inputs determines the position of the sunroof glass. As a limit switch closes, the 5 volt reference will be shorted to the sunroof limit switch low reference circuit, pulling down the 5 volt reference to 0 volts.
The sunroof control module understands the position of the sunroof glass based on the different input combinations through the sunroof limit switch soft stop signal and sunroof limit switch open vent signal circuits.
Power Sunroof Does Not Close
Perform the Initialization/Teach Process any time a new sunroof motor actuator is installed in the vehicle or any time an existing sunroof motor actuator is removed from the vehicle. Refer to Sunroof Motor/Actuator Initialization/Teach Process .