scratch build or modify, that is the question...

[Matt Tomkins]

for when i put Misty back together, i'm going to have to replace the wiring loom (old one so knackered, and damaged from trapped wires in the accident). I know it's reletively easy to buy a new one, but then i'll have to modify it to take the alternator, radio, hazards, fogs etc. I also want to use DIN connections or similar throughout, i.e. when coming through the bulkhead/going through to the wings on the lighting loom etc, to make removal of bits easy, and faults easy to trace (this is how we have wired the OUMF cars, and how most race teams wire theirs too.
My question is whether it would (and i think it may be) easier to start from scratch and design my own loom to my own spec. with lengths all made perfect for the route taken and the plug-connections in at strategic points.

Has anyone done this, and also has anyone got a modified diagram with lengths etc on it? (long shot, but someone may do :p) Also, does anyone know what ampage wires should be, and the best place to get a selection?

any help would be greatly appreciated.
thanks, as always,
Matt

[PSL184]

Dead easy to do. Using your old loom as a guide, lay it out over a length of ply or MDF. Tap in some nails at all the bends / junctions etc then lay the wires following the nails. Probably if you search Google for "Breadboard" you may get a better description and photos...

[Matt Tomkins]

i had to cut the old loom where it went through the bulkhead, but i like the thought -- could certainly work. confirming lengths with string i s'pose :p

[bmcecosse]

I have in the past designed and made a special loom for a rally Mini. Easy enough to do. But I don't agree with your connectors idea - every connection is a possible future fail point - and the basic loom is so simple - just run wires directly. I used all red wires and put ident numbers on the cable ends - mainly because i had a big roll of suitable red cable in stock! The harness was very far from standard - with duplicate switches for driver and navigator for lights/wipers/horn etc - and many fuses for individual circuits. It worked well!

[mike.perry]

Speedy Cables will make you a loom to your specifications

[les]

I would buy standard and modify as required, it's all measured for you, not to mention avoiding the hassle of finding the correct coloured wires and finding a large enough clean area to lay it all out, I made a harness for a ducati years ago, if I could have bought one I would have!

[dp]

When I replaced my loom, in a quite modified Minor I decided to buy a new Minor loom and then use the Lucas colour scheme for all the extras - as far as possible. That way the original Minor wiring diagram plus a sheet of Lucas codes helps me trace future faults. Well I hope so. I bought extra wire from http://www.VehicleWiringProducts.eu and lengthened or shortened existing wires accordingly. I also saved the good bits of wire from my old loom. You could just make the whole thing from scratch. I appreciated having some wires just fit as they were supposed to though.

As above I also avoid extra connections and use continuous runs or solder everything that doesn't need to be disconnected. Less points of failure.

I recommend a roll of masking tape which you can use to put temporary tabs with descriptions on every wire during construction.

[autolycus]

Autosparks will modify their standard looms if you tell them what you want, and are also an excellent place to buy cable and fittings from. I wouldn't add unnecessary plugs and sockets - as Roy says, it's connectors that cause a lot of problems on modern cars, and they all add to the cost. I prefer to stick to standard cable colours. You'll have to fit a lot of spade connectors and bullets to make a neat job, so splash out on a ratchet crimp tool.

Kevin