BMW 645Ci Sunroof Switch Replacement Cost

The sunroof switch is the mechanism behind the buttons pressed by the user in order to cause the power sliding sunroof to lift, lower, slide open or slide closed. It should not be confused with sunroof position switches or any other switch relating the function of the sunroof.

Any common user-controlled automotive switch operates on the same basic premise. When the switch is pressed a circuit is either closed or interrupted, which causes the electronic actuation of the connected system. In this case, pressing the sunroof switch, a multi-directional switch, will actuate the sunroof by energizing an electric motor. Depending on the direction the switch is pressed, the polarity of the sunroof drive motor can be changed to reverse the direction of motion. When the switch is released for the sunroof, the motor will lose power, and the sunroof is stopped. On models with automatic sunroof control, the signal is computerized, and pressing the button will alert the sunroof control module or body control module that the sunroof should move to limit, and the control module will power the motor until input from the sunroof position sensor or switch tells the control module the limit has been reached.

Failure of the sunroof switch will either result in inoperability of the sunroof in one or more types of functions, or the failure of the sunroof to cease functioning. For instance, the sunroof may lift or retract, but not close, leaving the sunroof open at all times, and the vehicle unsecured. Also, models that do not use sunroof position sensors to cancel the action of the sunroof will likely blow the fuse shortly after the sunroof makes it to one of its far parameters. This is because the motor can continue to run, but since it cannot open the sunroof, it will likely draw too high of an amperage for the fuse which provides power. Also, the switch may be visibly damaged, leading to an understanding that it must be replaced.

The sunroof switch is only considered urgent if the security of the vehicle is at risk, or the vehicle is in danger of water damage from rains. These two concerns lead to costly repairs or loss of the vehicle in either situation, so repairing a sunroof that cannot be closed is very urgent if the vehicle must ever be left outside and unattended.

There is no predictability when it comes to sunroof switch failure. These switches are very simple, handle low current, and are fairly reliable. However, water damage from a sunroof that does not have the drains cleaned as scheduled or is left open during inclement weather can cause early failure or temporary issues that may return.

When the sunroof will not do one or more functions on demand, the switch will likely be tested first. The switch can be diagnosed as faulty simply by testing for continuity across the switch when the switch is cycled through all of its possible settings. If pressing the switch does not create a continuous circuit,the switch will be proven failed.

Removal of the sunroof switch will likely require disassembly of the overhead console, removing the switch from the cover panel, disconnecting an electrical connector, and installing the new switch in reverse order. Some models will have the switch for the sunroof located on the instrument panel, in which case the switch may be removed without further disassembly, or the switch will require removing a larger access panel. In most cases it will be necessary to clean the electrical connector before reinstallation due to the high possibility of light to moderate water damage.

Checking your fuses first is always recommended when it comes to electronics. All too often an electrical component is replaced only to find it still does not function. This is because without a good fuse, the system will not receive power.

The trim panels, switches, lights, and other accessories mounted near the sunroof switches on the overhead console are typically brittle after only a few years. This is the hottest place in a vehicle, and water that may enter the vehicle will assist in weakening the plastic trim pieces and accessories. Great car should be taken to slowly remove these components to prevent their destruction.

This is an easy DIY for the auto owner who prefers to save a few bucks while servicing their vehicle. The replacement and diagnostic procedures are fast and easy, and the cost of parts is typically very economical. With just a little time, a multimeter, and a little patience, this job can be done without issue. The only other recommendation is to have a soft, durable, plastic spudger to use in removing those plastic interior components.