locating a power wire route through the firewall

[ssj2xxgotenxx 10+ year member]

I've done many installations on various cars throughout the years, and I always find myself wasting the most time on finding a hole through the firewall into the cabin. I've gone as far as drilling holes in the firewall, but that's difficult in respects to getting a good angle with a bulky drill. It's also dangerous because you could potentially drill through some important components.

So for all the professional installers who do installations day in, and day out. What are some key indications to look for to find a place to route the wire?

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[LeofromtheH 10+ year member]

i'm no professional installer, but when i run it though friends cars and what not, i usually look for where the factory wires are already running through.

they usually have some sort of rubber grommet to keep it watertight, so i run it alongside those just to keep from drilling holes

 

[iamamp3pimp 5,000+ posts]

i almost always drill a hole t the left of the gas pedal.

 

[Randy Savage 5,000+ posts]

I usually run it through the doorjam like all of the cool ghetto-style 'my friends cousin' type installers.

Werd.

Seriously, all depends on the car. Usually I'll try to locate a stock groment and see if I can get anything through that, if not, see if the area right around that is free and drill through there. I'll just play it by eye and I've never had a problem...

 

[bonesninja 5,000+ posts]

i usually drill a hole in the passenger side of the firewall. then i use those little conduit clamps to hold the wire in place. they have a screw on bezel on the back side then a clamp on the inside

 

[thatkidbob 10+ year member]

i usually end up drilling holes... i usually do quick installs, so i look for grommets, but if they're too small or not visible from both sides of the firewall it's hole time.

 

[Ctminime 10+ year member]

when i ran my 1/0 i just ran it underneath my car. works great and i dont have to worry about drilling thru any wires or anything.... i just drilled a hole in the bottom of my trunk in the bottom of the spare tire well sealed it with silicone and a conduit clamp and away i went...

 

[azbass 5,000+ posts]

automatics most always have a good knock out for the "clutch" to drill through. or has a groment

manuals are tricky.

and dont use that little conduit clamps like bonesninja posted. please.

 

[timvanderet 10+ year member]

whats wrong with the conduit clamp?

I've never used one, just curious

 

[knukonceptz 10+ year member]

Fastest way is to cheat - check out an online forum for that specific car, some one has already done the legwork for you and usually posted in a FAQ.

 

[luvinthebass 5,000+ posts]

I just follow the factory wire harness under the hood. Usually, it'll be a foor or two down on the drivers' side.

That seemed to work the best for me and i have a 2001 Taurus.

 

[spin dB 10+ year member]

I usually find the factory harness and run it along side of that and go through the gromet and then you are in. In my car for instance (2001 Olds Alero) that is not an option. I ended up running it through the gromet for the Steering colum. If that will not work I would look for a "knock out" where the clutch would be and buy a rubber gromet and drill, if there is not a "knock out" or if your car is a stick then you can either run it under the car and drill a hole in the trunk/hatch or you can drill in the floor of the passenger side this side is usually easier to get to and usually doesn't have as many vital components behind it

 

[ssj2xxgotenxx 10+ year member]

I just follow the factory wire harness under the hood. Usually, it'll be a foor or two down on the drivers' side.

Factory wire harness is usually the one that connected to the diagnostic port?

 

[bonesninja 5,000+ posts]

yeah i'm curious to know why the conduit clamp is no good, i've been doing it for years and not once has it ever failed, leaked or otherwise

 

[disturbedfuel15 10+ year member]

I usually just drill a new hole on the side of the steering wheel, along with a grommit. There's not much you can hit over there, if you drill down low enough.