A power sunroof can slide the roof panel open or closed. You can also tilt the roof panel up in the back to allow fresh air into the passenger compartment. When driving down the road this can also pull a vacuum and remove stale air from the interior cabin.
In most cases power sunroofs are not that much different than electrically operated power window systems found in most automobiles. Many common parts are shared such as system relays, a master control switch and the motor assembly to perform the movement.
Note that most power sunroof systems are protected by a circuit breaker instead of a fuse. This is in case the sunroof begins to bind. It protects the motor by opening the circuit breaker. Often when people have power sunroof problems they will begin to look for the fuse when there is actually none. A circuit breaker will reset automatically when it cools down.
Power sunroof operation
When you select the close sunroof position often the polarity is reversed to the power sunroof motor to run it in the opposite direction to perform the opposite tasks mentioned above. Some of the newest sunroof options include a solar sunroof that is available on many luxury models.
This feature uses elements mounted either in the glass or under the glass to produce electricity to power a ventilation fan inside the interior cabin. This solar powered venting system will operate even with the ignition switch off. The benefits are that it will provide a continuous flow of fresh air to the interior cabin.
Power sunroof common problems
Since a sunroof is part of the exterior surface of the vehicle a complete watertight seal is necessary. If this seal fails or the automatic drain becomes clogged with debris and water sits around the components the corrosion mentioned above will be accelerated. For this reason a very common sunroof problem is water sealing and drainage.
Diagnosing power sunroof problems is pretty straightforward. The first thing to check would be the circuit breaker. Next you would want to verify power at the motor connector. In that case you would be working from the load back towards the battery. If there is no power at the motor you can break out a wiring diagram and do some pinpoint checks at the relay and switch.
This next link will take you to a good place if you are looking for more information about wiring diagrams or online auto repair service manuals. Or you could head back to this blog's main page from this page about power sunroof problems.