SmarTire Hardwire Install FAQ
For those wishing to hardwire their SmarTire display/control unit, here are some instructions based on how I mounted mine. There is plenty of wire (length) to mount the unit just about anywhere in the cabin ... I chose to mount mine just left of the steering colomn on the wood trim. I really wanted to locate the display in place of the ashtray, but the unit is just too big. I selected the trim location as it is somewhat discrete, still easily visible and within reach when driving, and very easy to wire from here w/o tearing up the dash to find ways of hiding the wiring. Also noite: These instructions can be used to hardwire just about any accessory, such as a radar detector. 


* Please note that the following was performed on a '98.5 A4 2.8qMS, other models may be different. Also, I assume absolutely no responsibility for any damage resulting from the use of these instructions ... perform this procedure at your own risk *  Read through all of the instructions first. If you feel uneasy about your ability to do this job, consult a professional. On a scale of difficulty from 1 to 10 --  1 being easiest -- this job is a solid 1


What you'll need:
  • 15 amp automotive fuse (blue, aka "slotted" or "blade" fuse)
  • Fuse adapter for slotted fuses; Female connector crimp-on wire terminal (lower right of Photo 3)
  • Fork or Ring crimp-on wire terminal (lower left of Photo 3)
**all of the above are available at Radio Shack and cost less than $5 total ** 
  • Zip tie
  • 8 mm or 5/16 socket
  • Phillips screwdriver
  • Wire crimpers 
Hardwiring the SmarTire display:

On A4 sedans (not sure about the S4), fuse slot 27 (Photo 2) is powered and vacant, as this is the location for the Avant's rear wiper fuse ... So, I tapped into for it power.  This allows for the unit to power on/off with the ignition.  I found it easiest to work with the wiring *not* connected to the display unit I was ready to mount it...
1. Remove the AC adapter from the end of the display's wiring by unscrewing the plastic housing and removing the wires. 
2. Crimp on a female terminal to the end of the wire with the (black & white) striped sleeve -- this is your power supply / positive lead. 
3. Crimp on a fork (or ring) wire terminal to the other wire -- this is your ground / negative lead. NOTE: I used the fork type terminal for simplicity, since it doesn't require you to completely remove a bolt for mounting as does a ring terminal. 
4. Slip the fuse adapter onto the left prong of your 15 amp fuse. (see Photo 3 for example) 
5. Remove the fuse box cover and insert your fuse w/fuse adapter into slot 27 It may feel like you are "forcing" it -- just apply some pressure and it'll pop in. 
6. Determine how much wire you're going to need at either end -- for both connections inside the fuse box and to the display unit in the desired mounting location (Photo 1 shows where I chose to mount) 
7. Secure your ground wire using a bolt on the dash frame. I used the one at the bottom of the fuse box. (Photo 5) 
8. Fasten the power lead to your fuse by sliding the female connector onto the fuse adapter (Photo 4 and Photo 5) 
9. Connect the power cord to the back of the display/control unit and mount in the desired location using the supplied velcro. 
10. Once the unit is wired (and the display mounted) bundle the excess wiring and stuff it somewhere behind the dash. (Photo 6) 
11. Now tuck the exposed wire leading from the fuse box to the display unit into the crease below the [wood/aluminum] trim. Since the dash is padded it has some give and the wire should recess nice and snug between the bottom of the trim and the knee pad of the dash. (Photo 7) 
12. Replace the fuse box cover and you're good to go! Good luck!

Photo 1:



Photo 2:



Photo 3:



Photo 4:



Photo 5:



Photo 6:



Photo 7: