Sunroof wont open but the switch makes a clicking sound

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)
• Sunshade
• 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 .

Often can be the fuse. The sunroof on my '98 opened fine then 30 mins later would not close. Found a 30amp fuse burned out. A 2 minute fix. Fuse box is located in glove box. If you hear a click sound the instant you push the open button, then you might be a more serious issue. Beyond my knowledge

Most likely the fuse is burned out. Check the cars manual to find the fuse for the sunroof and check if it looks blackened.------------------------------------------------------------------------------
Diagnostic VAG

HAVE SAME PROBLEM ON MY ALERO , WOULD CLOSE TO VENT POSITION ALL OTHER FUNCTIONS WORKED FINE. TALKED TO A MECH. FRIEND AND FOUND A WAY TO CLOSE MANUALLY BUT YOU DO HAVE TO DROP FRONT LEFT CORNER OF HEADLINER.
THE MOTOR IS UNDER SUNVISOR AREA AND YOU'LL NEED AN ALLEN(SPELLING)SOCKET TO CLOSE ROOF

Sounds very much like you have a nick on the wiring and it maybe shorted, check your Fuses, it maybe a fuse, but if it's a nick in the wiring shorting, get it to a Garage to check, as it may cause a fire in the engine someday.

Hi,
Usually, when a part of car that is run by battery failed, first
thing to check is the FUSE from the main fuse box or
a fuse box somewhere under the hood. Next is to locate the
motor that drives the sunroof and have a qualified electrical
mechanic check the motor, If the fuse is Ok, and still
stopping, then check motor and you may find that only the
carbon is the problem. If still the carbon is ok and the
sunroof still stop, you may ask the mechanic to check and
test the "Stator" and "Rotor" that has failed and may require
rewinding of the coil wire.

Did you check fuse #16? It is 15A
If you know how to use a VOM (volts ohm meter) I write down the procedure for testing your sunroofs circuitry.

1. Check fuse 16 in fuse box
2. With a test light or with a VOM you will check if you have continuity from the fuse that powers your sunroof switch.
3. Check the black/white wire connected to the switch if you're receiving 11.5V min. If you do then you have power from fuse to switch.
4. Check if you have continuity for ground (-) from the interior light switch wire harness by probing the brown wire. If you do then you have a good ground connection for your sunroof motor.
   
5. From the fuse (16) and the yellow wire on the switch you should have 11.5V min when you actuate the switch.
6. From the fuse (16) and the blue wire on the switch you should have 11.5V min when you actuate the switch.
7. If no voltage in either #4 or #5 above when you actuate the switch then you have a bad switch.
8. From the switch to the sunroof motor you should have 11.5V min using the yellow and blue wire to the motor. If voltage is not present you have a bad connection from switch to motor.
9. If you have power to the motor and it doesn't do anything then you have a bad motor and needs replacing.
   

CHECK FUSE IF OKAY.CHECK TO SEE IF POWER GOING TO SUNROOF MOTOR SWITCH IF YES SUNROOF MOTOR COULD BE FAULTY OR IT NEED ADJUSTMENT.SWITCH COULD BE BAD.IF SWITCH IS GETTING NO POWER FUSE IS GOOD THERE IS A BROKEN WIRE FROM FUSE TO SWITCH.

Check the switches for a clicking sound if you hear a clicking sound then the switches are fine. Does the driver side switch work for the windows? Check it for the click sound. Make sure it isnt a blown fuse. If you have replaced the fuse and you dont hear clicking sound it might be the switches and you can find them at a junk yard. If you have tried all these things and it still doesnt work you might need new window regulators and/or window motors or it might be a wiring problem.