Wiring the switch for an LED light bar

[SoCalStig]

Good morning. I am new to the forums and am hoping that someone can give me a bit of advise. I have a 2006 Expedition Limited that I just purchased a 20" LED Light Bar for. I will be installing it behind the lower grille, and will be using a relay connected to the battery to power it. The biggest problem that I foresee in the installation is getting the wiring through the firewall for the dash switch. A quick look yesterday afternoon didn't reveal any easy ways to get the wiring from the engine bay to the passenger compartment. Can anyone give me some pointers about where will be the best place to run the wires to the switch?
Thank you in advance, and i look forward to hearing from anyone that has done one of these before.

 

[hendricksen11]

I will be looking for a very similar set-up shortly, so interested in the replies you will receive.. in the meantime you could look in peoples stereo builds as they will have probably found a decent grommet to pass much larger wire through.. If I see anything I'll update this thread

Edit: Oh and welcome!

 

[stamp11127]

Take a look on the driver side firewall where a clutch master cylinder would be located. I believe there is a grommet or depression where it would be located on the p/u's.
As far as wiring it, consider having it powered when the ignition switch is in the run position instead of coming directly off the battery. Rate the relay around 40-60% over the load the light bar will pull and fuse accordingly for the current draw on both the control and load sides of the relay.