Planning a rewire

Doing a rebuild on the series 3, involving a chassis replacement so everything will be disassembled. Series 3 wiring is dubious at the best of times, and after nearly 40 years I don't think any of it is worth bothering with. It makes little sense to rebuild the truck only to have fire hazards or be chasing corroded contacts forever. So time for a ground-up rewire.

My plans currently are:

• New fusebox under the passenger seat, with every circuit protected by its own fuse, plus large fuses to distribute power from the battery to each group of circuits. This fusebox to be be built with plug/socket connections to the main harness so it can be removed for maintenance/alterations. Planning to use this modular system to build it: https://www.polevolt.co.uk/acatalog/Modular_Fuse_and_Relay_System.html
• All high-current loads (headlights, glow plugs, starter solenoid etc) to be switched by relays
• Provision for some additional circuits- lights on the bumper, couple of extra gauges, radio/speaker wiring.
• Build the harness in 5 main sections- bulkhead harness, left and right wing harnesses, rear chassis, engine. Sealed connectors (e.g. Econoseal) in the engine bay/transmission tunnel and everything to be covered in split conduit (or harness tape where it goes behind the dashboard).
• Use of the proper Lucas colours where practical.

Any suggestions or things I've forgotten about?

Put in an independent isolator while your at it , maybe help prevent theft in the future

I would agree with your list, having done this I would say:
Hazards are a worthwhile upgrade but a right pain to get right
Run some extra power and wires to the rear, you will add things later (rev light, rev camera, rear 12v socket)
Keeping to the orginal colours got the better of me, it meant buying so much cable I gave up and used one colour for one set of related circuiits, I'm regreting it but I would have had to buy 20 or 30 reals of cable and end up with most of them used for a foot or two.
Do a cicuit diagram as you go, again I wish I'd done this. Thought I'd be able to recall it later when I had time to do it, no.
The things that i found really useful were decent crimp tool, a gas soldering iron, lots of coloured shink sleeveing and coloured cable ties, the black loom tape that looks like fabric, and an earth block on the bulkhead to run all the earth returns to one place.

I'll be adding a more subtantial centre panel (mudstuff or similar) so hazard switch will go there along with a few other bits. Lots of wires go to the hazard switch as the feed to the flasher relay loops through, but fairly logical once you figure it out.

Going to measure the old harness as a guide for making up the new one amd getting the lengths right- I've done a bit with work and basically every wire has a number, a start point, end point and a length. Takes a while but excel is always your friend and you end up with a methodical plan.

When did wire get so expensive. I've always been able to scrounge whatever I needed from work until I retired, now I need some and have been surprised at the cost of it, especially in Halfords the robbing gits.

Col

Colthebrummie said:

When did wire get so expensive. I've always been able to scrounge whatever I needed from work until I retired, now I need some and have been surprised at the cost of it, especially in Halfords the robbing gits.

Col

Click to expand...

Price of copper has gone up a fair bit, plus Halfords of course add their usual markup on bits that are much cheaper elsewhere. If I can't get all the right colours, I might compromise slightly and use coloured heatshrink every few cm on plain wires. Every connector will have the pinout recorded for maintenance/future alterations.

Not sure yet whether the cooling fan will be electric or engine-driven. Ideally I'd like to keep the 19J viscous fan for simplicity, but space between the engine and series radiator might be a bit tight. If I go electric, I'll make this as a self-contained wiring harness so it can be removed later on if needs be.

Try here
https://www.ebay.co.uk/itm/3m-lengt...af7ca9b0:m:mJWU2q3Oj8f2ozQS-7BZxOQ:rk:79:pf:0
or vehicle wiring products.
http://www.vehicle-wiring-products.eu/?jssCart=1e723229d8d572ca88b69887b9c6cd70