Thread: Wiring through D4 firewall

The easiest spot is through the grommet above and to the left of the brake pedal (where a clutch pedal mechanism would be). If you download a Traxide install manual you will find a good description and pic of the spot.

If your going to the trouble of running a wire through the firewall, use some trailer wiring cable, (5 wires in a group). It's no more work but future proofs you.

Regards
Trevor

Originally Posted by ytt105

If your going to the trouble of running a wire through the firewall, use some trailer wiring cable, (5 wires in a group). It's no more work but future proofs you.

Regards
Trevor

Well, yes if you'll only ever use low current accessories. But if you want to run a second battery or power an Anderson plug for a caravan, you'll need the whole of the small diameter grommet.

There is another one that those of us with Millennial Immobilizers use which is near the brake M/C. You have to penetrate the insulation under the dash to get it through though.
Every time I run a cable down the side of a vehicle, I pull a 6 core 14/0.20 security cable with it. If I need more current I just use that to switch a relay at the point of distribution. It's not ideal, but has proven to be very useful over the last 33 years.

I have some 7 core large trailer cable (1.84mm2) which has come in handy also, and on Aliexpress you can get silicone multi-cores between 5-7 cores at up to 2.5mm2.

Originally Posted by bordertech

Hi, I want to fit a driving light switch in the cab. Where is the easiest spot to get wiring through the firewall from the engine bay without pulling half the car apart? Its a 2012 SDV6. Thanks.

I thought D4's had an extra light switch on the dash that is pre-wired?