GD427 MK IV

GD427 MK IV
What my car should look like when finished - Stoneleigh 2015

Wednesday 28 June 2017

Wiring, Wiring, and more Wiring

I started to put some of the wiring together for the body.  GD provided the harness for the body in two parts - front and rear.  I have thought long and hard about extra wires to put in, how to run the loom and where it can all fit.

I started by laying it all out and using the provided wiring diagrams and notes, tried to understand where it all goes and what additional items I would like.  In addition to the already added to engine loom (here), The list seems endless...............


  • The Aeromotive fuel pumps came with their own wiring looms which contains a 50A fuse and a relay along with all the supply / feed and trigger cabling.  These just needed a mounting location and the wires trimmed to length.
  • The Innovate Motorsports Wideband Lambda sensors require some additional fuses (5A per controller) and a relay(s) along with wiring.
  • Since the GD provided heater fan comes with 3 speeds, I wanted to have that availability so needed to add an extra wire.
  • The GD supplied fuse box comes as an 8-way unit which is already used up.  I bought a 16-way unit so all the fuses will need transferred to the new box and additional fuse wiring added.
  • In the GD build notes, it mentions about removing the green wire from the washer pump plug and replacing with an earth & the horn relay requires the purple wire removing and replacing with an earth on pin 85. 
  • I prefer a minimalistic look in the engine bay, so have decided to run all the engine loom plugs & earth in through the bulkhead along with the ECU wires / connector which will run behind the fuel pressure regulator.  Wires need extending to permit plugs to enter cockpit from engine bay, and the mating plugs re-routing back into passenger footwell.
  • Original holes for Engine loom connectors / fuse box requires filling and gel coat applied prior to sanding and polishing.
  • Additional ignition & permanent 12V supply wires run to the additional fuse box for future connections.
  • Earth & supply wires run from new relay for lambda sensors to fuse box and to controllers.
  • Additional 50A fuse supply inside cockpit - just one single 25mm² 12V hi-flex cable from the battery along with earth connection - require to solder all the 1mm² cores into a 25mm² through crimp and crimped on a 25mm² hi-flex cable to go to the battery.
  • Additional earth bar located inside the cockpit for future earth connections fed with 25mm² hi-flex cable.
  • Superseal connectors for all connections and convoluted conduit for protecting the cabling under the wings.
  • Additional wires for Coolant level switch which is located in the radiator feed hose, and for the heater control valve.
  • Spare wires for a switch mounted to the clutch pedal - to be wired up to the starting circuit so the clutch pedal has to be depressed to start.
  • The GD fuel pump wire will not be used, so will be a spare going to the rear of the car.  The CANEMS ECU will trigger the Aeromotive pumps - 1 master pump and a switch will control the 2nd pump.
  • 6mm² wires need to be installed for the Corsa Power Steering column from the 2nd 50A fuse.  VSS signals and others require to be run up to the power steering ECU.

The amount of times I have had the loom in, out, taped up, tape off, tape on, in, out is ridiculous!  It isn't far away now, so I will post what I have done so far.  I am waiting on some more convoluted conduit for the front indicators to finish them off.


Original GD Relay panel (7of)


Slot cut above heater to allow cabling to pass through


Wiring loom pulled in temporarily to check lengths prior to fitting superseal connectors


Loom near bonnet hinge


All front wiring passes through the bulkhead outside of the engine bay


Stainless battery tray supplied by GD - modified to allow fitment of slightly longer battery......


Relay holders and fuel pump relays / fuses mounted



Original 8-Way GD supplied fuse box


Additional relay (Twin) added for Innovate Lambda sensors


Additional 50A fuse holder added (with aluminium mount)


Earth bar mounted


Superseal connectors used and convoluted conduit used for protection


Wiring for O/S repeater



3 comments:

  1. What wiring diagrams have you got Jonathan? I don't think Ive got any issued by GD?

    ReplyDelete
  2. I'll email you what I have. I have my notes written on which may or may not help you.

    ReplyDelete
  3. Jonathan, doing one myself which I know is a slow burn (5 yrs plus into the build!). 8 pole engine loom wiring now. Radiator switch, did u add into radiator and did u wire to switched 12v?

    ReplyDelete