Unused large drivers side hole in firewall only on the A4?

[Melvin.Ross]

I'm on the last legs of a new stereo install and was looking for a place to run wire into the cabin. I saw other threads mentioning a small grommet in the floor of the drivers side, but then noticed this much larger opening when under the hood.

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Inside of the car, there are two nuts that appear to hold this cover in place, but that's it. I haven't found any mention of it in any of the other threads, so wondered if it was only unused on the automatics.

 

[Old Guy]

Its hard to figure out the exact position of that plug from the photo; but, if its on the firewall to the left and a touch above the brake MC and the car is an auto I am going to guess that the it would be occupied by the clutch MC on a standard equipped car. The spacing of the bolts sort of looks correct for the flange on the clutch MC.

 

[drew]

That is for the clutch master, not used on the AT.