I'm trying to run a wire from the engine compartment through the fire wall to a switch I'm placing under the dash....can anybody help??

 

Best p[lace to go is follow the hood release cable. Driver's side under the master cylinder.

 

Just aft of each front wheel liner is a passthrough grommet that the main wiring loom goes through. There is an additional "nipple" that you an pierce and pass through any wire up to an 8 gauge cable. You must remove the front wheel and both front and rear wheelhouse liners to acess.

 

I just wanted to echo Tiberius1701's post. This is REALLY easy to get to. Here's a picture from the passenger's side of my '06 GT.

 

I agree, sorta.
You do not have to remove the wheel, but you do have to remove the fender well linings and I you can run much bigger than 8 ga through them. I ran 1/0 ga Power wire for my audio system through that same hole

 

Thanks everyone...I assume it becomes obvious where wire comes through on the passenger compartment side.....