Next up - The dreaded loom

[baz-r]

i used a rapid fit loom but i would pass on them. its a great loom but has very little info that comes with it and the support form rapidfit is very poor.

i made my own seprate loom for my fuel injection and i find its the easy way to do it

the key is to have an idea what is where and wire it up when the car is almost finished

a good selection of split conduit makes a easy and tidy way of an install

[Enoch]

If you still have your build table you could drive a nail or two in at each location where something needs to be wired. Draw in things like headlamps, side lights, indicators etc so you can see how many wires you have to run and where they need to end up. Draw in two fuse boxes - one for permanent live things eg side lights, hazards, imobiliser etc and one for everything that needs to run off a switched supply. You will end up with a group of wires going to the back - left indicator, right indicator, lights, fog light, reverse light, tank sender, fuel pump - these can run as one loom down your tunnel. In the tunnel you will have handbrake and reverse switches, you may also have a wire for an electronic speedo if you are using one.
Take it one wire at a time and it all seems pretty easy. I would tend to have all my engine management relays mounted near the ecu, it makes life easier for testing and debugging at a later date.
You can then do the same trick as you did for all the stuff at the back with the stuff at the front. Run wires for hi beam, low beam, side lights, left and right indicators.
Do similar with all your engine sensors, don't know what your ecu needs but it will most likely have coolant temp, air temp, fan control, cps etc. Draw on your plan where they all are and allow a wire for them. Keep your wires plenty long at the moment, use unique colours for each circuit and keep a note of them. It really is very simple once you get rolling.
There are pin outs for most ecu on t'interweb, there are circuit diagrams showing how to wire up hazard switches - these are still simple but cause more confusion than just about any other item.
Hope that helps, you can do it, there are many people a lot less smart than you that have done it. Just because there are lots of wires does not mean it is complicated, it just means you have to do the same simple things more times to finish the job.
Best and all that,
Enoch

[Eddy]

Thats an excellent write up of how to go about it, Enoch. Makes me feel like I would be able to do it, but I've already asked Alan at Premier to make me up a loom. It will free me up some time to work on other parts of the build and hopefully make for a nice easy installation.

I've also been persuaded by a few friends that have popped over to see the build to buy a digidash (I had planned to use the standard Sierra dials), so I'll need to wire that in and make up the loom for megajolt and associated sensors, so still a bit of wiring to get my head around!

[Stot]

One of the things that was putting me off was the number of different colour wires to buy, seemed like a mine field, until I read a guide that suggested only using black wire, and use bands of coloured shrink wrap at each end for identification.

Cheers
Stot

[alga]

Hm, I tore apart the donor loom and ended up with lots of different colored wires to make my new one.

[Stot]

Originally Posted by alga

Hm, I tore apart the donor loom and ended up with lots of different colored wires to make my new one.

That was the other idea but 25+ year old wires are already broken down an amount, often I strip wires and there is black oxide layers on the copper.

Cheers
Stot

[flyerncle]

Anybody if and how you can get rid of bulb failure relay from the Sierra loom.