Running wire through the firewall for the 6

[Nepharius]

I am trying to run a single little wire from near my battery to my steering wheel for an LED which will tell me when the meth pump is running. I have run into a pretty serious problem though. I can't for the life of me work out how to get the wire through the engine bay. I found that rubber grommet behind the battery so I thought I could get in through there. After much cursing and struggling I managed to put a hole or two with a coat hanger, but after it punches through it seems to hit something hard, possibly the firewall (although I am a little worried the bunch of wires )

Is there a simpler way (preferably with a guide) for our cars without having to drill through? All the guides I can find are for american cars with their LHD witchcraft.

[Toddy22587]

If you follow the bonnet release cable you'll find a spare gromet next to it where it passes through the body and comes out under the guard on the front right wheel. you can then run it along with the other cables under the guard and bring it out behind the drivers side headlight. This is where all my cables run. I decided to run 2x 5 core trailer wires so i'd always have spares for future use.

Hope that helps

[MZSPD6]

I installed a boost gauge and gave up trying to get through where you are trying to, I drilled through the firewall after reading a few posts on mazda6club.

I just installed an alarm and the instructions said to run the siren up through the grommet in the upper left kick panel then run it throught the wheel arch under cover back in to the bonnet. This wont work for a boost controller as it's long way to run a air tube but for a LED power wire it would be no problem.

[Nepharius]

I'm a little embarassed to say what I did...... This is about the dodgiest way to do this possible, but the LED is basically a indicator to tell me if my Meth system is working properly (IT IS NOT *angryface*) and is temporary. If you open the drivers door you will see a few holes just on the right of the weather seal. The top left of which you can stuff a stiff wire down until it appears in your engine bay. However this is the opposite side of the car to where I needed the wire to be so I have 3m of thin wire tracing the front of my engine bay. Tidy? No. Effective? Questionably......

[KRNAGE]

not sure on the 6 but on the 3 where you describe the grommet behind the battery, is where i have my LED/Map switch, and wiring for my gauges running through
To get access I remove the glovebox and you see the rubber grommet. Push it aside and voila your in the engine bay................but your way works too

[Doug_MPS6]

I covered this a while ago. I drilled a 5/8" dia port through behind the battery and fitted a grommet. You could go up to 7/8 with care. Start small. There is a lot of insulation to drill through too. The internal fibreglass insulation will wind up around your drill bit. Do it a bit at a time. Be patient.

The position has to be quite precise. There are two air-con pipes passing through the firewall. You have to drill at a point ~25mm (+/- 5mm) right of a centre line drawn between the centres of these two pipes (as seen when facing the firewall when standing in front of the car with the bonnet open) and at the same level as the midpoint between the two pipes.

Remove your battery so you can manoeuvre the drill and keep it straight, perpendicular to the firewall, and remove the glove-box so you can see the inside where the drill comes through, and drill a small pilot hole first. There is also a small bit of external soundproofing to push to one side at this point inside the engine bay.

I have run my boost guage lines and my other leads through this one port. Don't forget the grommet or cable ducting or the cables etc will chafe. You can access the hole from inside the glove-box aperture when the box is removed so you can feed wires both ways easily.

No responsibility taken if you mess it up or drill through something critical. It works fine for me.

[AlTee]

On my 2005 6 (non MPS) I used the grommet for the accelerator cable - pushed another small hole in it and pushed the wire through ...

[Doug_MPS6]

Sure. It's OK for some applications, but often you need direct power from the battery, and all my other leads for various things, such as boost sensor, need to run up the LHS of the engine bay towards the battery. It's an easier side to work from too, although often it involves running internal leads across the car behind the gearbox tunnel/stereo setup. Just be careful you don't foul the accelerator cable or lead setup if you use that grommet.

[rayd]

Sorry to bring up an old thread , but I'm having trouble finding the other cable exit side if the firewall in my 6MPS.

I was able to feed the cable into the firewall entry from behind the car battery, buy in the passenger foot well I can't see the exit side!? I've taken out the glove box and fished around behind it and can't find it

Help please?

[Doug_MPS6]

RAYD, It's essentially a double wall. If you didn't get the location right as per my instructions, then the wire may be behind the aircon ducting. That is why I suggested a pilot hole as a probe first. Also if you didn't drill far enough, your hole may be in the right place but invisible behind the internal insulation which is quite thick. You do need the glove-box removed to see it. If you get stuck I'll take a photo of the correct location and email it to you. PM me yr email address if you need this. Be carefull not to drill through your aircon ducts or something else critical.