Redoing wiring harness

[MB140]

GreenV8S said:

drcox99 said:

That’s what I was hoping to do, what’s the best way of doing that? Just straight up rip the current loom apart?

I've done this a couple of times for engine looms, but not for a whole car. Given the age of the car I'm assuming the wiring is relatively simple so it ought to be relatively easy.

I'd do it like this: Label all the connectors that terminate the loom, and label whatever they connect into. Take lots of pictures showing where the loom fits, especially where the loom is physically supported and how it passes pipes and brackets. Physically remove the loom from the car, keeping it intact. Get a board big enough to lay the loom out on without different parts getting in the way of each other. Splay it out so that nothing overlaps and all the runs are straight. Doesn't matter whether the layout has any relation to the geometry when it is installed. Add something to secure the loom so that each junction and each end point is fixed to the board. I like using velcro cable straps for that, but there are plenty of other ways. Draw out the route the loom takes between the mounting points. Trace out for each connector where each wire goes to, and document it, including the wire colours. Order 50% more wire than you think you need in each colour/size from your favorite supplier. Mine is VWP. Buy really good quality terminals, and the right tool to crimp them. Buy a wire labeler. Dymo sell some good ones. Buy lots of heat shrink tubing to connect the wire ends, and plenty of loom tape, and whatever you want to use to protect the loom. I like braided sleeving for this but others use split corrugated tube which is easier to use. Lay each new wire on the board and terminate the ends to match the original. Use lots of cable ties to keep it roughly loomed and 'dry fit' it and test in the vehicle. If it fits and works, take it out and loom it properly before the final fit.

^+1
I spent 6 months in a cabling bay doing wiring looms for aircraft. We used to use the reusable cable ties during production of looms. Very handy as you can tighten them to hold wires in place and then loosen them to add more as you build the loom. But the above is pretty much all the advice you should need.

1 final thing. Please use the correct crimp tool for the job. It saves time in the long run as fault finding later on when you have an intermittent fault because you used the wrong tool for the job is a real PITA.

[drcox99]

Not really, but I want speakers, Bluetooth

[Penelope Stopit]

The job you are about to do is very simple, you don't need to mess about with using a board, you don't even need to take note of where any cables branch out from the main loom
Due to you getting rid of some of the circuits there aren't many circuits that you will be needing
The most important thing to do is keep hold of all the old loom until you are up and running with the new one, there may be a few plugs/connectors/terminals that you will need to re-use when building the new loom

Best looms don't have plugs and sockets for connecting front, rear and engine looms together, the whole object of the job is to make an all in one loom if possible. Front, rear and engine looms with inter connecting plugs and sockets are made to keep the job simple for mass production.
Mass production wiring looms are a load of bks, I suggest you keep well away from mass production layouts.
Choose a position inside the car for where the relay plate and fusebox are going to be located, the majority of cable runs will end up running to or from the location of the relays and fusebox

The whole building of the loom is all about "ins" "outs" and "straight throughs" for the "ins" you need to list all the switches needed and then calculate the number of cables and cable lengths from the switches to the relays, fuses or components, this is depending upon how you have chosen to wire the circuits

Now "outs" can be calculated the same way as "ins" but this time the cables and lengths are calculated from fuses/relays to components

In amongst the "ins" and "outs" there will be runs of "straight throughs", these "straight throughs" will be all the cables that aren't being fused or relayed - a good example being - temperature and fuel gauges are wired directly from the gauges to the senders and should not be cut anywhere along their runs

Put pen to paper and perhaps post it here of your cars components layout.....the rest really does all fall into place and i or A N Other will gladly help you on your way

One other thing you need to pay most attention to is the run of the loom, build the loom along good runs where it won't be in contact with sharp objects and won't be getting clamped between any brackets

When you know the locations of all the components being fitted you can calculate the earth cable sizes and runs

Rolls of tape and lengths of cables are all you need to get started

Enjoy it....that's the main thing