Getting wires through the firewall

How can I run wires through the firewall? I have been trying to wire my ambient temp sensor, but I cant seem to find a way to get the wiring through the rubber grommet in the firewall. How do you guys do it?

 

There's a little rubber tip on the bottom side of the rubber grommet that I cut off and ran mine through.

 

Grab a metal coat hanger wire, duct tape the wire to it and pierce the rubber grommet until the wire gets to the other side of the firewall. There's a couple radio/light how-to's that have pictures of this.

 

What Brewsy said^^^

 

If it's not a really big wire I found you can pass through the opening were the hood release cable passes through the large rubber boot with out cutting, stabbing or using any excessive force. That's what I did with the signal wire for my fog lights.

 

Thanks gents. That was driving me nuts. I didn't even think of the hanger.
I saw the little nipple thing on the engine compartment side, but i didnt think if that.