Originally Posted by 2012subisport
I am adding an amplifier and running a 4 gauge power wire through the firewall. I found a rubber plug/grommet next to the brake booster that looks like it's unused but I can't find it on the cabin side as I think floor insulation covers it. Has anyone used this plug/grommet for an amplifier power wire feed through the firewall? See photo with red circle around the plug/grommet. Thanks...!
I ended up using the large diamond shaped plug just below the red circled one. Pulled it out, made a small hole in the center of it, feed the 4 gauge wire, there is some insulation on the other side I made a slit in and pulled the wire through. If anyone needs pics, I will take and post both under hood firewall side and cabin side.