Introduction: Radar Detector Mirror Tap Installation for BMW X5 (F15)

In May of last year, I traded in my 2011 X5 (E70) for a 2017 X5 (F15) and therefore I had to redo some customizations. One of them includes installing some hardwiring for a radar detector (was using an Escort Redline, but now a Uniden R3).

This time I was going to attempt a "mirror tap" install instead of the usual "leach power from the cig lighter and run a really long cable under the dash and under the A-pillar".

I tried two different mirror taps ($20-$30 each!) and neither had long enough taps, so last night I built my own for about $1.00 (because I already had most items on-hand) and about an hour of my time. This instructable covers the actual mirror tap install process.

Sorry I didn't take photos of the cable-making process. It was getting dark outside and I just wanted to get it done. I added a wiring diagram though!

Steps to make cable:

  1. Strip wires off both ends of USB cable.
  2. Insert red and black wires on one end into RJ-11 connector as shown in photos.
  3. Crimp RJ-11 connector closed.
  4. Insert a 2 Amp fuse into the fuse holder.
  5. Cut wire and strip wires of each end of fuse holder.
  6. On other end, slide shrink tubing on then solder red wire of USB cable to one end of mini fuse holder.
  7. Slide shrink tubing onto black wire then solder black wire to another black wire of the same length as the fuse holder (so the whole thing is of equal length).
  8. Straighten paper clip, then using wirecutters, cut into two equal lengths.
  9. On the other end of the fuse holder, slide on shrink tubing and then solder to one paper clip segment.
  10. One the black wire, slide on shrink tubing and then solder to the other paper clip segment.
  11. Once you have tested the wire with the radar detector, use heat gun to shrink all tubing and then cut paper clip segments to length as needed.


Tools used:

  • Pry tool
  • Wire cutter
  • Wire stripper
  • Soldering iron
  • Heat gun
  • Crimp tool for RJ-11 (phone) connectors (example)

Parts used (keep in mind that I already had everything on-hand):

  • Dead USB cable (with the end connectors cut off)
  • Mini Fuse holder (18AWG) (link) THIS IS THE ONLY THING I HAD TO PURCHASE.
  • One 2 Amp Mini Fuse (link)
  • Some RJ-11 connectors off eBay (only need one, but always good to have spares)
  • Shrink tubing
  • Some small zip-ties
  • A single, small paper clip!

Step 1: Start by Prying Apart the Mirror Cover

Insert a pry tool or something flat but NOT made of metal into the center of the cover and press.

The cover should pop apart easily. In fact, your finger or thumb might even do the trick!

I've added photos of the inside so you can see how both halves clip together.

In the unlikely event that you broke the cover, I've added pics of the part numbers.

Step 2: Examine Mirror Wiring and Connectors

There are two connectors under the cover.

We will be working with the larger one (black) and not the smaller pink one.

Step 3: Slide the Connector Out and Remove the Male Side

The black connector sits inside a small holster to keep it from flopping around.

Slide the entire connector out of the holster then press the retaining tab to release it.

This will give you more space to work with connector.

Step 4: Note the POWER and GROUND Wires

This took far too long for me to figure out, but the wires we need to tap into are as follows:

  • POWER = GREEN with black stripe
  • GROUND = BROWN with black stripe

If you want to check it for yourself, you may need to attach (tape) some 1-inch segments of a paper clip to your voltmeter's probes in order to get them deep into the connector.

Step 5: Install Mirror Tap Probes Into Connector, Then Secure and Reinstall

It will take some trial and error for the paper clip end of your wiring to sit deeply into the connector.

I recommend you have your vehicle powerd on in ACCESSORY mode and your radar detector connected and powered on while you do this to ensure that the everything is secure.

Once satisfied, use a couple of small zip ties to hold the wiring together and keep the probes from slipping out.

Tip: If you haven't physically installed your radar detector yet, put a microfiber towel on the dash and then put the detector on top of that to prevent it from sliding off the dash during testing.

Step 6: Carefully Insert All Wiring Into the Cover and Reassemble

Because of the small diameter of the old USB cable, I was able to run easily the wiring between the mirror cover, windshield, and headliner without having the drill out any part of the cover itself (as others have done).

I recommend going with a more "permanent" type of windshield mount.

This eBay seller is where I bought mine over the years for multitple vehicles and radar detectors: