The sunroof port has four drains, one at each corner. Each of these drain holes delivers rainwater through the car’s body and out onto the road. The holes in the front corners drain through the A-pillars to the forward door jambs of the front doors. All you need to do to access the ends of these drain channels is to slide the sunroof to the rear position and open the doors. Then you snake a speedometer cable or a similarly rigid wire or cable through the drains on each side of the car until it appears at the other end. Remove any debris that emerges.
The rear sunroof holes drain through the C-pillars down to an area that is concealed by the rear bumper cover. In order to access these rear drains, first you must remove the rear bumper, which is fairly easy to do. Keep your drains clean and you should expect never to find a big puddle in your seat after a big rain.
10 gauge audio system wire in a ten-foot length to snake through the sunroof drains.
At the front corners of the sunroof opening (with the glass slid back into the roof), you can access the drain holes that lead down through the A-pillars. Push the wire down through the hole.
Here is the wire as it emerges from the drain in the passenger-side front door opening.
You have to do a little more work to access the rear sunroof drains. First, you have to remove the rear bumper to access the drain outlets. Start by using a Torx T-25 to remove the one fastener in each rear fender well that connects the fender liner to the rear bumper.
Open up your trunk, lift up the carpeted panel that forms the floor of the trunk, and locate the two fasteners on each side. These are 17 mm bolts; the rear ones hold these tie-downs in place, so they will come loose as you remove the bolt
These are long bolts, but they are fairly easy to access and remove. Note the hold-down and how the bolt passes through it. You’ll tighten these to 17 ft-lb during reassembly
Once these fasteners are removed, it’s time to get physical with the bumper. First, push it forward, toward the front of the car. Make sure to push both sides of the bumper forward equally
Once the bumper is moved forward, this edge of the bumper is revealed in the rear wheel well. You can use this edge to push the bumper down and release it from the triangular plastic bracket that hold each end of the bumper in place against the chassis.
With the bumper pushed forward and then down, you should be able to pry it outward slightly to release it from the plastic bracket seen here. These are similar, if not identical, to the brackets found at the ends of the front bumper.
Once the bumper is free, pull it straight away from the back of the car.
Here is the reason you need to pull the bumper straight back – these impact rams extend deep into the body of the car on each side.
Each of these rams has a plastic end that interfaces with the car’s body. These can fall off while you’re removing the bumper or be lost within the body, so be sure to put them back in place before you replace the bumper.
This is one of the deep recesses that receive the impact rams of the rear bumper. Note the accumulation of small stones over the years
Here is the exit of the rear sunroof drain on the passenger side, just behind the plastic bumper mounting bracket. Simply snake the cable up through the drain.
You can tape up the end of the cable in order to help it pass through the body without catching.
As you push the cable up into the drain, the center tube can get pushed up into the body; you can hold it in place with some Vice-Grips.
Place the sunroof in the tilted position while you chase the rear drains; you may be able to pass the cable through with the sunroof slid back into the roof, but I was not. The rear holes within the sunroof opening are virtually impossible to find, so it’s simply easier to push the cable up through the drains behind the bumper cover.