I never cease to be amazed at the number of enthusiasts I meet who are quite happy to undertake any of the mechanical aspects of a car build or restoration and yet they run a mile at the prospect of wiring the car themselves. Most of us take the practical approach when confronted by something we know nothing about: we press gang a friend who can help!
This is all well and good, but if you can’t find a victim then your options rapidly reduce to having to pay someone to do it. While this is not a bad thing in itself - after all, some things are best left to the experts (wheel alignment leaps to mind) - the problem is that any wiring job, especially one like custom wiring a car from scratch takes a fair bit of time, particularly if you want a neat and tidy job. Unfortunately this will cost a lot of money, assuming you can find an auto electrician who is willing and capable of tackling the job...
Wiring a car yourself is one of those jobs that looks impossible at first glance, however, further examination will reveal that in reality it is NOT beyond the average enthusiast. The key is to think about what you are doing, plan thoroughly and take your time. Physical wiring is merely a case of stripping wires and soldering terminals on, which takes a lot less skill than welding, panel beating or painting!
I have completely wired three cars now, including my own car twice (due to a total rebuild and upgrade). The last thing I am is an electrical engineer, so if I can do it there is honestly no reason why you can’t. The three jobs I have done from scratch have all included EFI engines and I am about to embark on another complete car with EFI. With the acquisition of a few specialised but relatively inexpensive tools you can wire your car as good as if not better than any professional, and save yourself money while you are at it.
I have read a number of articles over the years in magazines on how to do car wiring but they have always struck me as being somewhat superficial. My intention is to provide a step by step guide to wiring a car yourself, and I have endeavoured to fully cover all aspects of the subject in sufficient detail to enable you to successfully complete the job. Whilst I have endeavoured to ensure a high degree of accuracy I accept no liability if your car catches fire!
Methods of Wiring a Car
There are four main ways of wiring a car I can think of:
- using a complete loom from a donor car
- creating your own wiring loom from scratch
- a combination of a and b
- paying someone to do it all
This article deals with wiring from scratch as it is the most complicated but the principles apply to any major wiring job. Although the last option is always a fall back if things go horribly wrong, they shouldn’t if you plan carefully!