I like to mount the radar detector between the mirror and the top of the windshield. This keeps it out of the way but still close to my field of vision.
What you need:
-Radar Detector Hardwire Kit (with radar detector)
-10mm Socket, extension and wrench (possibly Universal adapter)
-U-Ring Connector or O-Ring Connector
-3M Spring Connector or solder and solder gun
If you like your radar detector high on the windshield, the sunroof switch is the best area to grab switched power.
To begin, you will need a hardwire kit from your Radar Detector manufacturer. The kit should have two leads, one to ground and one to power. The power lead should be fused.
You will want to start by gaining access to the sunroof switch wiring. To do this, you will need to remove the switch and light panel. The panel has 2 clips along the front edge (nearest to the windshield). I was able to slide a butter knife between the headliner and the panel to push the clips back. This took me a long time. The other way to do it is to
carefully pull down the headliner and slide a finger or two in to release the clips. The clip locations are shown in the following image.
Additional Information regarding the clips:
This thread on e90post may help in showing the tabs better than I explained.
There are two tabs along the front edge. They are located approximately at the maplights. You need to push the tabs toward the back of the panel to release the front edge. The front edge needs to be released first.
Once the clips are released, lower the front edge of the panel and then slide the back edge slightly forward to release the entire pane. The panel has a control unit with 5 connectors. You may want to undock the connectors from the panel so the panel is not in your way. You will be looking for the switched power wire in the indicated connector. It is pin #3 and is a
green and white wire.
You will need to remove some of the electrical tape around the wiring. Once you have located the wire, tap into it and connect the power lead from the RD hardwire kit.
With the power connected, you will need to ground the second wire on the hardwire kit. If you look to either side of the sunroof motor, you will see a 10mm bolt. I used this bolt to ground the wire.
I used a 3M U-Connector as the bolt is a bit tough to get to and could be even more difficult to re-install. The U-Connector allowed me to back the bolt out a few threads and then slide in the connector. You may need to use a Universal Joint along with your socket to access the bolt. Tighten the bolt back down.
With the connections made, route the connector for the radar detector out between the headliner and the windshield. Feel free to take your time on stowing and routing the wiring to make sure you do not end up with any rattles or vibrations. I wrapped the fuse for my Escort 8500 in felt before completing installation.
With the wiring all done, you can test the radar detector. With the car in accessory mode (key in and once press to the start/stop button), the radar detector will have power. Re-installing the sunroof switch panel is the opposite of removal. Install the back edge first and then snap in the front edge until the clips click.
