A well planned and carefully constructed wiring loom is critical to the success of any car build. The use of high quality connectors, the right automotive cables, the correct crimping equipment and crimping techniques are key. Its also important to create a drawing or "run list" so that the wiring loom and main connectors can be determined. This also ensures that changes or additions can be easily made in the future.
We really enjoy wiring up our vehicles. Looking under or behind a dashboard and seeing all the cables laid out neatly and logically is very important. We also ensure that the harness is designed with bulkhead connectors in firewalls and panels. Various harness fastening clips are used to ensure it stays in place. Every harness should be able to be disconnected and removed from the vehicle. We do not make looms that require cables to be cut to remove them from the vehicle. This helps during construction as the looms can be made out of the vehicle in a neat and concise manner and fitted to the car.
Of particular importance is the planning and execution of the dashboard wiring loom. Many of our vehicles have removable dashboards and we wire those through one or two large connectors so that they can be quickly and easily removed from the car. We also use multiplexing systems in some vehicles to reduce the number of cables to and from dashboard switch-gear.
We like to start with the dashboard when wiring the car. It tends to be the most complex part of the wiring so we enjoy doing that first. The dashboard wiring for the XJ13 can be seen below.
Some wires are labelled on the dash to help the owner identify on some of the more critical wires.
We use Deutsch connectors for most of the interconnects in the vehicle. They are highly reliable, sealed and we have a good range of them in stock.
We use the correct terminals and crimping techniques for each of the cable sizes used throughout the vehicle.
The dash harness plugs into the main under dash fuse box assembly. Again this can all be easily removed from the vehicle to work on it.
For quick changes or to service on the XJ13 a fuse the panel can be flipped up from under the front hood and checked without crawling under the dash.
All wires are left un-taped in internal areas where protection is not required. It makes future changes much easier. We also don't need to tape as there is no mess to hide.
We also installed a remote battery disconnect to enable the electrical system to be isolated from within the car. We ensure these disconnects incorporate bleed down resistors so that alternators are not damaged and internal ignition cut circuits to eliminate engine run on.
Mega and Midi fuses are also used to protect main power feeds from the battery and alternator. Where cable assemblies will be exposed to debris in wheel wells etc. we cover the harnesses.
Main battery looms also use pass-through connectors in firewalls to ensure they can be easily removed and will not chafe and short to the chassis. All signal wires use double shielded Teflon insulated tin plated multi-core cables. These are very compact and ensure light reliable looms can be built.
The heat shrink boots on all the large connectors are not installed and shrunk down until the car is completed. We also run additional spare cables through the vehicle to assist with future additions.
With the majority of the wiring completed attention will soon focus on the interior trim