Any experience making new pass through holes in firewall?

[Prommy]

I'm looking to run new wires through my firewall for relay controls, power and various antennae; too many to simply use the left/right ~2" grommets on either side behind the dash. I'm a tad nervous making educated guesses on good drill spots, so looking for advice.

Anyone else install 0.5-1.0 inch pass throughs? Where did you locates them and roughly how thick is the firewall (I think it's 2+ sheets of steel with space separating them)?

 

[TowMeOut]

Do you really need to pass through the firewall or can you go through the floor pan, along the frame rail, and up into the engine compartment? I've only run some 6awg for my fridge (2 pieces) but there seemed to be a lot of unused gromets and space around the existing wiring harness. Maybe look a little harder for alternatives before you start drilling.

 

[Drunner97]

You'd be surprised how much wire will fit through the left and right grommets.

 

[svana]

I did and kind of wish I hadn't. Nothing bad has happened but just unhappy about it when I think about it.

 

[t-rex grrr]

You'd be surprised how much wire will fit through the left and right grommets.

He's right. I have a total of four sets of wires (12 wires in total) running through to four switches.

Just use a really sharp knife to make a X, then pass your wires through.