Originally Posted by Bad_Mikey
I would like to see where it comes through on the inside of the car. I can't use the diamond due to it already being used.
It's really simple, get a flash light and start looking for reference points. Go back and forth from engine bay to inside, once you think you've located the same spot. Use a small poker to test your spot. Something like this...
Can be made out of an old flat head or phillips screwdriver.....
or you can also pull those rubber plugs out sometimes too, which makes it even easier to test, you'll still need to poke something thru though since the inside firewall is typically lined with a foam/rubber matting.