Webasto Hollandia TVS 900 ST Sunroof - 2009 GMC Denali

Webasto Hollandia TVS 900 ST Sunroof Switch Test

It should come as no surprise that Webasto, the world leader in aftermarket sunroofs, has released another really cool addition to your truck that looks, performs, and enhances just like optional factory equipment. It may surprise you, however, to find out how cost-effective a sunroof installation is and how much value it adds to your truck's bottom line. Often times, checking the sunroof box at your local dealership means also agreeing to a "premium" or other overly-dramatized package deal that quickly adds up to thousands of extra dollars, with parts you don't want or need. Thankfully, Webasto has a new line of inbuilt series of sunroofs that incorporate twin vents for the ultimate in form and function. Dubbed the Hollandia TVS 900 ST, this sunroof is the world's first true twin vent sunroof and allows you to control both glass panes, including combining them for a true open-air feeling. An illuminated control panel uses Soft Touch technology to easily open, close, vent, and even program your favorite position. Optional rain sensors and automatic closing upon ignition shutoff are just a few of the new Hollandia features. With a three year/36,000-mile warranty, you get peace of mind on your investment, and at $1,095, you don't have to check every option at your dealership just to get a bit of fresh air in your truck.

Arriving at Webasto's Dealer Service West, in Santa Fe Springs, California, head installer Ramon began the teardown of our '09 GMC Denali by removing the headliner, which required removing the sunvisors and gaining access to each pillar. He then used an air chisel to remove the factory roof support bar.
Arriving at Webasto's Dealer Service West, in Santa Fe Springs, California, head installer
Using the appropriate template for the Webasto Hollandia TVS 900 ST sunroof, Ramon took measurements to center the location of the area to be cut. Each measurement was double-checked and then the template was taped to the roof and traced with a marker.
Using the appropriate template for the Webasto Hollandia TVS 900 ST sunroof, Ramon took me
With the interior covered and seats protected, Ramon drilled four holes at the front of the roof and then used an air chisel and air nibbler to cut out the hole.
With the interior covered and seats protected, Ramon drilled four holes at the front of th

The tape served two purposes: one was to protect the paint while cutting and the second was to give Ramon a small space cushion for the cut. As you can see, this Crew Cab Denali is going to have a real open-air feeling with such a large hole in the roof.
The tape served two purposes: one was to protect the paint while cutting and the second wa
Using an air sander, the rough edges around the cut were smoothed out. This is why having the taped cushion is important, better to sand down a tough area than make the cut too big.
Using an air sander, the rough edges around the cut were smoothed out. This is why having
With some help, Ramon installed a brace jig to compress...

...the new sunroof frame to the roof and get the mounting location perfect.
Webasto supplies these roof frame supports and as you can see on the left, Ramon had to modify the bracket for the Denali installation. Four holes were drilled into the bracket and will serve as the self-tapping screw location for the roof skin.
Webasto supplies these roof frame supports and as you can see on the left, Ramon had to mo
Using the modified bracket, it was secured to the sunroof frame, which was then in turn attached to the Denali's roof using the supplied screws.
Using the modified bracket, it was secured to the sunroof frame, which was then in turn at

The sunroof frame was now supporting itself and Ramon was then able to remove the frame jig.
The sunroof frame was now supporting itself and Ramon was then able to remove the frame ji
Included in the Webasto kit, this weatherstrip piece will seal the roof to the cab. Automotive-grade silicone was used inside the weatherstripping to keep an airtight seal around the factory roof ribs.
Included in the Webasto kit, this weatherstrip piece will seal the roof to the cab. Automo
We were now ready for the large Webasto Hollandia TVS 900 ST sunroof.