Rear wiring loom

There are four main looms for the car:
1. Front
2. Rear
3. Dash
4. Engine

The Font loom has already been installed, although not exactly as per the GD manual, see this link for the blog post.  The dash loom can be purchased from GD (which is probably preferable if using the standard layout) however I will likely create my own as my layout will be different.  I already have an LS3 engine loom, that will stay in the cupboard until I get the engine.

To start with a pilot hole was drilled from the boot in the bottom left hand corner above the rear axle tunnel, this appeared behind where the passenger seat will be. I then opened this out to around 15mm and cut a strip out below this to allow the loom to fold downwards.

The loom is then fed through bit by bit from the cockpit, around the near side and behind the boot latch striker plate. The front part goes down the rear bulkhead, along the transmission tunnel then half way up the front bulkhead where it will meet the front loom behind the dash.

Within the boot, the loom follows the corner down the axle tunnel, across the floor and along the rear edge finishing at the offside rear lights. There are 3 main bunches of wires:

1. Fuel system (fuel pump, level sender)
2. Nearside rear lights
3. Offside rear lights

There is also a lead just as it enters the boot for the number plate light and provision for reverse and fog are available at either side rear lights.  The loom comes with crimped bullet connections but I've changed these for Superseal connectors (for the lights at least) as they lend themselves better to being disconnected/reconnected repeatedly and offer a more OEM look.

Drilling hole in to cockpit area

Loom behind passenger seat position (looking rearward)

Number plate light lead just inside boot

Fuel system bundle

Nearside lights

Loom goes behind boot latch plate to offside lights

Superseal plugs

Rear loom connects to front loom behind dash (black & white plugs)

Front wiring loom

The front loom has been a bit of a puzzle, especially within the cockpit area. I started by identifying and labelling the various parts of the loom using a combination of GDs wiring diagrams and the written instructions. Although this isn't difficult, it is time consuming but definitely time well spent and it certainly helped make sense of how it would be routed.

The standard GD method routes the front part of the loom out in to the engine bay through a 44mm grommet with the engine loom connectors, it then goes under the lip of the bonnet opening. I want to keep the engine bay as tidy as possible so I altered this slightly.

I pulled the front part of the loom (lights, radiator fan and horn) back through the big grommet leaving just the two engine loom plugs and the earth leads to go through the grommet. I then drilled a 20mm hole above and right of the heater ducts (looking forward) and routed the front part of the loom through the wheel arch compartment before going through the inner wing and appearing under the lip in the engine bay.

The loom then splits adjacent to the bonnet hinge; headlights/indicator/side repeater back through the nearside inner wing to the left and the rest to right under the nose cone and through the offside inner wing. The horn lead sits on the engine bay side of the nearside inner wing and the radiator fan cable hangs down in the middle under the nose cone.

Within the cockpit the relays have been mounted upside down in the nearside footwell and the heater fan & battery cable fed through the same hole as the front part of the loom in to the nearside wheel arch compartment.

Grommets have been used where the loom passes through bulkheads and it's all held in place with P-clips.

Relay block fitted with self tappers, just spotted that it's not level so adjustments necessary 

Nearside wheel arch. Head and side light cables to the left, side repeater cable going from left to right

Loom along inner nearside wing

Loom across nose cone, the cable dangling down is for the radiator fan