Lucas Wiring Colour Guide

Based on a page by Chris Kantarjiev of The Dimebank Garage with several additions and modifications by Skye Nott.

Any manual should have a wiring diagram (Haynes is fine). You may find it helpful to enlarge the page to 11x17 with a photocopier and trace circuits with coloured pencils. Most electrical problems are caused by:

1. Bad ground connections
2. Corroded bullet connectors
3. Bodges by the DPO (Dreaded Previous Owner)

I recommend replacing the fuse box outright if it looks old and corroded. It is an inexpensive part and will save you a lot of headaches down the road.

A pink eraser or 600 grit sandpaper can be used to clean contacts, and a smear of dialectric grease will help prevent future corrosion.

Major MGB wire colour groups: Main Color Purpose Brown Hot all the time, unfused Purple Hot all the time, fused White Hot with ignition on, unfused Green Hot with ignition on, fused

Many British designed vehicles use colour coded cables to assist in identifying the various circuits in use. This is an extract from BS-AU7a 1983 Colour Code for Vehicle Wiring, from the British Standards Institution, 2 Park St., London W1A 2BS.

(Note that these colour codes may not apply directly to older cars. For example, the wipers on cars up to 1980 (at least) are not on a separate fuse circuit, so they are not orange, but green. Check the schematic for your car to be certain. - cak)

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Many of the usual suspects carry Lucas bullet connectors. A few carry reproduction wiring harnesses. But very few carry the properly color-coded wire, and most of those only carry a small selection of colors and sizes.

However, there is one place that I've found that carries the whole gamut:

British Wiring Inc
20449 Ithaca
Olympia Fields, IL 60461
(708) 481-9050 voice & fax

They have every color combination listed above, in lots of sizes, as well as connectors, clamps, lamp fixtures and other random bits and pieces that you'll need. I've been very happy with the products I receive from them. Be warned that wire is often backordered and may take a couple of weeks to arrive. They have a nice catalog that's free.

Here are some other sources that have a more limited, but sometimes better stocked, supply:

British Pacific Ltd
3317 Burton Avenue
Burbank, CA
(800) 554-4133

Narragansett Reproductions
Box 51
Wood River Junction, RI 02894
(401) 364 3839

You may also want to check out the MG Experience Store, the MG Experience Specialist Directory, and the Monster Vendors list for more British wiring supply options.