Electrical question: How do I get through the firewall?

[Martinjmpr]

For those who have put on aftermarket radios or other electricals, how are you getting from the passenger compartment to the engine compartment? I can see a big rubber grommet on the upper left of the firewall with a bunch of wires going through it, but I can't figure out how to run a wire in through there without damaging the grommet. Any other ideas? On other vehicles I've owned there has been at least one rubber plug I could pop out to get through the firewall but I can't find one on my 99 SR5.

Thanks in advance for any help.

 

[Blanco]

Normally with those grommets you just have to pop a new hole through them. They appear to 'seal up' around whatever wire you run through there. Most people I've seen use a coat hanger to pop a new hole then tape a wire to it in order to feed it through to the cabin or vice-versa. I'm not certain if there is a 'cleaner' method for doing this?

 

[momo.75]

I don't have a third gen, but this should work. What i have done before was to take a coat hanger and straighten it out, then tape the wire to the end of it. Then you should be able to wiggle the hanger through the grommet and the other wires, then pull your wire through. Just make sure not to force it through. You don't want to cut the insulation of any of the other wires.

 

[theizzardking]

coat hanger or if you like tools, this is cheap and works well for cars and trucks....
50 Ft. Nylon Fish Tape

 

[Stick Figure]

I learned a long time ago to just drill a new hole for my own grommet. I've seen guys tear up the stock wiring trying to go through existing grommets. I've seen even more guys not get the stock grommet sealed back up and have problems with water trailing along the wiring right into some of the electrical components. I usually try to plan ahead with what I'm doing and run everything at once. Drill the hole, clean up the edge, install the new grommet with a little RTV to make sure the raw metal edge underneath is sealed from rusting. After i run the wires through I use a bit more RTV or silicone to seal the wires passing through the grommet. Black is always preferred if it is in a visible location. Unless of course you plan way ahead and track down a factory style grommet that can be sealed with tape and silicone internally.

 

[KAILUAZ]

Good timing as I'm looking to wire up my front fog lights. Is there any particular place that is better to dill a new hole? I havent dived under the dash yet to take a look.

 

[Elton H]

there should be few empty ones look on the drivers side

 

[Stick Figure]

If you have an auto there is always the spot where the clutch pedal and master cylinder would mount. This is usually particularly easy because the sound deadening under the dash is all ready perforated, and there is good room on both sides of the firewall for drilling purposes. If you have a manual and don't have these spots open, you'll just have to look around and make sure both sides are clear before drilling.

An automatic center punch is a great tool to have for this to make sure the drill bit doesn't walk away from where you want the hole.

 

[Maxil]

I would suggest not using the grommet that the main electric wires are running through. I used the one closer to the center on the drivers side, it is empty and meant to be used for other things. It is easier to run a wire from the engine compartment to the cabin due to its more difficult location under the dash. Once you poke through though, it is very easy to get.

I have lost count of the wires through mine and planning a couple more soon, I just use silicone to make darn sure it is sealed up nice.

As a side note, that main grommet is in the drain location for rainwater, it comes right down past it. If you somehow mess up and don't have it sealed right, you may end up with a mess inside. The previous owner of mine did that and I had the joy of cleaning up after.