Wiring Diagram
This is where the diagrams you have begged, borrowed and stolen come in, however, any bits you have not been able to get diagrams for you will now have to work out. You can do this by using the continuity function of your multi-meter, which allows you to figure out which connections go where under various switch positions etc.
This is actually quite easy if you take your time. Just make a drawing of the terminals on the item and see which ones are joined together. Obviously an idea of how the device works is useful and once again the wiring diagrams or parts catalogue drawings will come in handy, as there are generally only a couple of ways of wiring, say, windscreen wiper motors. Some components you can carefully remove covers from to see how the internal connections are made. It is a bad move to try hooking power up to things and seeing what happens...
Once you have worked out how each bit works you need to integrate the lot into a wiring diagram. I try to think of the car as three main systems - power supply, car electrics and engine electrics/electronics. I draw out the wiring diagram with the power at one end supplying a common ‘mains’ with car systems off one side and engine off the other. This results in a tidy diagram overall and a logical map to find your way around. Design one circuit at a time, and when you have it done, transfer it to the overall diagram. It is a good idea to have a large overall diagram - it makes it a lot easier to understand - A1 size graph paper is good and only costs a couple of dollars a sheet. The Fraser was all put on one sheet - including the entire EFI loom
Obviously there will be links between some systems but try to keep these as neat as possible so you don’t end up with a tangled mess. Most modern cars switch the earths for many circuits - this method provides the most fused protection, however, there is no reason to complicate matters more than you have to, so apply a little common sense to prevent running wires to and from a remote item - switch the power and earth at the component. Be aware of how each switch operates - does a two position switch turn off position one when position two is turned on, or are they both on?
Remember, it is your car, so you can do what you like. You may want to have it so the radiator fan runs whenever the engine is hot, even when the car is turned off - it is up to you. The thing to remember is that you don’t want to turn the car off and have indicators or something else still working that will flatten your battery. Make a complete diagram and wire the car to it. Remember to modify your diagram as you go so that it accurately reflects the finished job. This makes it a whole lot easier to fault find on later.
