I want to run some wires through the firewall to the cabin for sensors and gauges, does anyone know the easiest route to take to go through the firewall?
I did'nt want water leaking onto my accelerator pedal.I routed wires through the r/h wheel well. You'll need to remove the plastic inner guard panel and the r/h panel in the cab (the location of the panel is the same as on the L/H side that covers your computer) you'll see a flat section of steel. I used a 19mm hole saw and cut through. If you can get an extra grommet, same as used for the wiring for the side repeater lense, use this and some marine silicone to route the wiring through and seal it up. With the wiring through the body route the wiring through the grommet for the repeater lense wiring and your through to the engine bay.
Go through the grommet next to the brake booster. It's where the clutch cable would come through if it was a manual. As for leaking through that grommet, I have never had a problem in my VS, and neither have any of the customers cars who I, and just about every audio installer in Australia, have done it for.
I doubt you'll find any spare run of power wire sufficient for an amplifier sitting around in there. But that's besides the point, this is for sensors so i'm assuming huge runs aren't needed. Anyways, go with what people have said if you have an automatic, look on the firewall and there is a big oval shaped rubber grommet that won't have any hole in it or any wire running through it. It will give you PLENTY of room for the task.