Tools and Equipment 

Its about now you need to buy or loan the tools you will need. A decision needs to be made on the physical method of wiring a car. I am pretty one eyed on this front and regard solder and heat shrink as the only solution. Sure, it takes a lot longer than crimping fittings but it doesn’t fall apart after six months. I know car manufacturers and aircraft companies crimp, but they use far better tools and fittings than you or I are likely to buy. Remember that you will have some wires that connect directly to the battery without fuses - do you really want to risk that wire falling out of a fitting and shorting to earth?

ToolShopping

• Soldering Iron - don’t mess about, buy a 60 watt one. 20 Watt irons are great for building circuit boards but you want some serious heat. About $60 from Dick Smith etc. 
• Multi-meter - either digital or analogue (needle on a dial or digital readout). Get one that measures resistance, continuity and Volts. These get expensive very quickly so get the cheapest one that will do from Dick Smith or the like. Probably about $60. 
• Solder - resin cored electrical solder is the only way to go. It is quite surprisingly expensive and you use a fair bit. Buy at least 100 grams if doing a whole car from scratch and be prepared to buy more if you waste as much as I do. 
• Heat Shrink - great stuff, comes in a range of colours and sizes. Shop around electrical wholesalers. 
• Side Cutters - for cutting wire. 
• Heat Shrink Gun - great if you have one, or else use a hot air paint stripping gun. Buy a cigarette lighter if you don’t. A hairdryer may work, if you are allowed to use it in the shed. 
• Wire Strippers - the $ 10 pliers type work fine if you don’t have access to a fancy one, however, a professional type one is a really sound investment. Don’t mess around using side cutters - it is a waste of time. 
• Long Nose Pliers - used for crimping terminals on before you solder them. I will explain later. 
• Bowl of Water - for cooling insulation that starts to melt after you heat the wires too much when you get it wrong! Good for burns to fingers too... 
• Insulation Tape - buy good quality - 3M etc. 
• Cable Ties - far better solution than taping wire together. More on this later. 
• Wire/Terminals - as required. You will need varying lengths of wire in different colours and thicknesses, so find somewhere with a good selection that is willing to sell by the metre. Electrical Wholesalers like Ideal or J.R. Russell can be good, and will often sell heat shrink etc way cheaper than hobby shops. 

You will be buying quite a lot of stuff, especially if you are using new components. A good auto electrical supplier or someone like Lucas will get a fair bit of money out of you so see if you can cook up some sort of deal to get a good price on all the bits and pieces you need because you will not buy it all in one trip! Places like REPCO don’t stock all the specialised wire and terminal bits you need but can help with the hardware.

Soldering 

The method I use for soldering is a little rough and ready but it works. Once you have cut the wire to length slip on the relevant insulating sleeve or heat shrink and strip the insulation off the wire. If you are joining two wires together strip about 15 mm off each and twist them together. If you are placing a terminal on the end, strip about 5 mm and using the pliers crimp the bare wire to one set of lugs and the insulation to the next. Then hold the wire/terminal against the soldering iron. You need to place some solder on the iron to get the heat to transfer to the bit you are soldering. Then you just apply solder to the wire/terminal and dunk it in the water if the insulation starts to melt. A 60 watt soldering iron provides sufficient heat that tinning is not necessary. Crimping the terminals on first prevents you needing 6 hands to do the job.

Terminals 

Terminals come in a variety of types and sizes which correspond to current rating. The most commonly used ones are 1/4 inch female spades. These come in two types: solder or crimp. As stated I use solder ones. There are also latching and non latching terminals. The latching type have a wee lug that locks them into relay mount blocks, plugs etc, while the non latching ones do not. Non latching tend to be a tighter fit on the male as they do not have the plug to hold them in place. The same is true for male spades.

Bullet connectors come in slightly different types as well, basically English and Japanese design, and they are not compatible so some care must be taken to get the right ones. A sample is recommended to get the right match.

Eyes come in varying wire and eye sizes too, so ensure you have sufficient ‘thickness’ to cater for the current the wires carry.

If you are splicing into another loom you can either join the wires or try to remove the terminals from plugs and change the wires at that point. A jeweler's screwdriver is handy to unlatch the terminal locking lugs to allow removal.