Where do I run a wire through the firewall(s)
 

I know some of you have had to run a wire for (foglights etc) through the A4 firewall(s). Where's the best place to run the wire through, and how do I find it?

Thanks
(searched the archives, but there was only one post about the vacuum line)

Antony

Depends on the year
 

Some have a grommet to the right of the battery (see pics).

If you don't have that, you can run through ECU box, but I don't recommend this for power wire for an amp, but it's fine for boost line.

<img src="http://24.26.38.255:8080/audi/boostguage/rear_firewall_grommet.jpg">

Run the wire(s) in and out from the ECU box.

Try going through the ECU housing.
 

If you're facing the front of the car, there's also a rubber grommet left of the steering wheel column to run wiring through as well.

Thanks for your help. I'll start looking...!