Audi A4 B7 & B6 Escort Passport Hardwire DIY

Hardwired Radar Detector Install

Here is a step-by-step guide to hardwire an Escort Passport radar detector to your Audi A4, S4, or RS4. It should work for all model years but I know for a fact it will work for B6 and B7 models – and this will also work on just about any radar detectors, including Valentine One and Beltronics. This setup will make it so your charger cord is not visible, and the detector automatically turns on and off whenever the key is in the ignition and the car is turned on. This is great because it eliminates the need to turn the radar detector on and off yourself, as well as it looks a lot cleaner. It is also recommended that your radar detector is placed as high as possible, so this setup will give you maximum radar detecting capabilities too 🙂

Hardwire Instructions

Step 1: Buy the Necessary Supplies. You can get everything you need from Amazon:









If you want to source the products elsewhere, here is a breakdown of what you need:

  • A radar detector of choice. I recommend the Escort Passport 8500 X50 as a good value.
  • A radar detector hardwire kit, which is usually specific to the brand of radar detector you have
  • A mini fuse tap. I bought mine from Pep Boys for about $11, and it was called the MINI Add-A-Circuit. You’ll want to get one good for up to 10 amps.
  • Tools: Wire crimpers, wire connectors, electric tape, flat head screwdriver and wrench.

Step 2: Take off your fuse cover by opening your drivers side door and sticking a flat-head screwdriver in the crack to pry off the cover. The cover should come off without much effort.

Step 3: Locate a fuse you want to tap. I chose Fuse #16 which is the garage door opener. This fuse is a switched accessory, which means that it turns on and off whenever the ignition is in accessory or ON mode. Any fuse will work that is between 5 and 15 amps and turns on/off with the ignition…

Step 4: Install the fuse tap in accordance with the instructions, and connect the positive (red) wire of the radar detector hardwire kit to the wire coming out of the Add-A-Circuit using the supplied wire connector, being sure to crimp it at multiple locations.

Add A Circuit Fuse Tap Install

Step 5: Connect the ground wire of the radar detector hardwire kit to the bolt right above the fuses, as pictured above

Step 6: Test it – plug the hardwire kit into your radar detector, turn the ignition on, and make sure the radar detector powers up. If it doesn’t, check all of the connections. My hardwire kit had a loose connection in the middle of the wiring where it split into smaller gauge wiring, so double check everything. They’re cheap kits, so chances are not all of the connections are great. Once you’ve gotten it working, you’re good to start making the install look good.

Step 7: Place your radar detector where you wish. I chose to the right of my rear view mirror. Be sure to place it low enough that you can still open the passenger side vanity mirror so your passengers can still use the mirror if they want.

Step 8: Plug the hardwire kit into the radar detector, and then start from the radar detector and start tucking the wiring in the headliner while working your way back to the fuse box. The wire should tuck in pretty easily into the headliner and wrap around the base of the rear view mirror. When you get to the pillar, it should also tuck easily in there until you get all the way back to the fuse box.

Step 9: Once it’s all wired how you please, do one last test to make sure everything works. Assuming it does, use a generous amount of electrical tape to secure all connections and tape the extra wire out of the way.

That’s it! This should take about 15 minutes as long as you don’t have to try to find any loose connections or hit any snags. Let me know if you have any questions in the comments section. There is an alternative method to doing this where you tap the power source of the sunroof, but in my opinion that requires more effort and more risk, since you could potentially short something with the sunroof if you’re not careful. This is a super easy method, and since you are using a fuse tap you don’t have to worry about shorting out your radar detector as well.

Nick Roshon

Nick has been an Audi owner and fanatic for the last 10 years, and started Nick's Car Blog in 2009 to share DIYs and pictures of his A4. Currently he drives a 2012 Audi TT-RS, and has previously owned a B7 S4, B7 A4, and an 82 Audi Coupe (GT) LeMons race car. In his day job, Nick is a digital marketer and lives in San Diego, CA, USA.


  1. Looks great and seems pretty easy. I’m hoping to try this pretty soon. Thanks for the great write up!

  2. I’m going to try this with my Valentine One – I just ordered the direct wire power adapter kit today. I figured I could run the wire just as you described, so I’m happy you confirmed it will tuck right in there…thanks!

  3. Hey Nick, First thing nice write up!

    I have a question, I tried your tutorial with my B7 A4 and when I tried the add a circuit with the garage door opener fuse I got no power…(my car has this fuse empty by stock). So I tried various other fuses and got the V1 to power up no problem, however it always stayed on. Do you know of any other switched accessory fuses? or does the orientation of the add a circuit make a difference ? (flipped one way vs another?) sorry for the lengthy comment. any advice would be appreciated!

  4. Thanks Rino! I’d test a few options and see what does and doesn’t turn on/off with the ignition. Just plug it in, turn ignition on/off and see what works. Read the description of each fuse on the inside of the panel and you should be able to make a pretty decent educated guess as to what is always on versus what is switched on/off with the ignition.

  5. Hi nick,
    It seems this add a circuit has 2 fuse slot. So i have to put the original garage opener fuse in one the slot right? My escort used 2 A in line fuse. How many amps do you think i should use?

    Thks in advance

  6. Yeah, the original fuse goes in one, and then the second one can be for your radar detector – a 2A is fine, if that’s all your detector requires…I think I went with a little higher but as long as it gets enough juice to turn on you should be fine…

  7. Thanks for the write up. Did this yesterday with my Valentine V1, with a few changes. The fuse tap i bought ended up only fitting in the bigger fuse slots so i ended up tapping the one associated with the electric motors on my sideview mirrors. Having some difficulty getting the wire to stay in my headliner though. Any idea on how to get this to stay? I have a few but wanted to check in first.

    Also, i bought this mount because i have had issues with the ones provided by valentine ( )


  8. Will – double-sided tape is probably easiest, but I’m sure there are other methods too. My wire stays just fine though, are you sure you pushed it in far enough? Use a flat headed screwdriver and jam it in there deep enough,it should be fine on its own.

  9. I jammed it up there a few times and it kept slipping down.

    I ended up wrapping the wire in one spot in electric tape (maybe about 4 or 5″) to make it more girthy and then i jammed it up there. Used a long spudger i had laying around, since it fit and would not damage the wire. Seems like it should hold now. Thanks!

Leave a Reply

Back to top button