Modular Wiring Loom

One of the things I wasn't particularly happy with about the standard car was the wiring loom. Indeed, I made several modifications during my initial build and incorporated these into an auxillary loom. This auxillary loom included, amongst other things, an extra immobiliser circuit, electronic speedometer wiring, connection to my ECU loom and a radiator fan override switch.

I feel that the shortcomings of the standard Tiger loom are mainly down to its suitability for the purpose. The literature for the kit said it was designed for the car, but there were several areas where the loom was the incorrect length, several essential features were missing (fog light tell tale, brake fluid level warning switch connections and indicator side repeaters) and, in the case of my 12 fuse loom the lack of fuse on the electric fuel pump feed could potentially be very dangerous were the pump to seize. This doesn't affect the 6 fuse loom, and others with the 12 fuse loom have said their fuel pump supply was fused. If you have a 12 fuse loom and the electric fuel pump supply isn't fused, then please install an in-line fuse in the positive supply to the pump.

The standard loom works with a few modifications and many of the shortcomings I identified can be sorted out easily by joining other pieces of wire to the loom, but it then becomes more difficult to trace problems should anything fail and I didn't feel that it is a particularly elegant solution to the problem.

Whatever my feelings about the supplied loom, one thing for certain was that I required extra facilities above those provided, including a reversing light. Having built the auxillary loom and then misplaced the diagrams, the easiest solution was to rebuild the loom to my specifications from scratch.

Apart from my requirements for additional circuits, I wanted an easy way of isolating separate parts of the loom for testing and possible removal from the car. This was particularly important for the dashboard section as wiring up the back of all of the instruments isn't a particularly easy job. The solution to this was to build the loom in modular sections and use polarised locking multi-plug connectors to join the various sections together.

With these requirements in mind, I worked out all of my circuit diagrams and then worked out the physical layouts of the wiring for these. The logical splits of the loom with multi-plugs yielded 5 separate sections for the front, rear, dashboard, scuttle and column controls with a central section which connected all of these together and to the fuse box.

I originally mounted the relays and fuse boxes horizontally on the battery tray panel, but a relay that vibrated loose was the cause of the only breakdown (so far!) that stopped me in my tracks unable to move. If possible, I wanted to mount the relays and fuses vertically in a plastic box, so the process of finding a box suitable for use at the fuse box started. I ultimately found one at Maplin.

Fuse Box Installed In The Car
Fuse Box Installed In The Car

Work has been progressing very slowly on the wiring loom, I forgot just how long it took the first time round! The loom is almost complete, only requiring connection to the rear lights, but has been completely tested. I only had one problem whereby I connected two wires the wrong way round to the wiper stalk control which meant that in the off position, the wipers were on permanently and in the on position, they parked. This was easily resolved by swapping them round within the housing.

The loom has been completed and tested successfully with everything working as it should. At some point, I will update this page with the circuit diagrams should you wish to build your own loom as I have.

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