Need some Electrical Experience Help

During my Defender TD5 engine rebuild I would love to replace the engine loom, I have a used loom which I am assured is OK and today I started the task of replacing it but hit some snags.

Old loom is YSB000860, MOD B Issue A
New loom is YSB000882 Mod J Issue B
In the box under the seat my loom looks like this

Red plug, black relay shoe, brown power feed, and the blue plug which is taped up and not used no more
There are two yellow relays but they are connected into the loom with the Black plug

On the new loom I have

There are two extra Yellow relay shoes

At the other end where the loom gets to the cylinder head the OLD one looks like this



But the new one has two extra leads with plugs like this (the ones with pipe clips on them)


Has anyone had experience of this and know whet the two relay shoes and the extra two plugs are for, I dont want to fit this only to find that its no good and I have to go back to the old one.

I’d start by laying out the loom over the engine and you may be able to work out what’s what.

I got a new loom for my Defender (haven’t fitted it yet) but I know at the time it was cheaper to get the one with the aircon plugs etc than it was to get one without. As long as the loom is for your engine (10P or late) then it will probably be fine and might just have some extra connectors for thing you don’t have.

Later today I had time to Google the part numbers, it seems my old harness doesn't have AC but the new number has it. And as you say the AC one is cheaper.
I'm now guessing that the relays are for the AC clutch and probably the rad cooling fan, and the two plugs are for rad cooling and clutch.
I think I will trust that the basic looms are the same and the extra bits are just add ons for the AC, so if I fit the loom and just tape up the spare plugs it should work.
I hope.

raywin said:

Later today I had time to Google the part numbers, it seems my old harness doesn't have AC but the new number has it. And as you say the AC one is cheaper.
I'm now guessing that the relays are for the AC clutch and probably the rad cooling fan, and the two plugs are for rad cooling and clutch.
I think I will trust that the basic looms are the same and the extra bits are just add ons for the AC, so if I fit the loom and just tape up the spare plugs it should work.
I hope.

Click to expand...

You can add AC easily too now if you want!

Would be interesting to hear how long it takes you to change the loom! I’ve been putting it off for ages!

tom1979 said:

You can add AC easily too now if you want!

Would be interesting to hear how long it takes you to change the loom! I’ve been putting it off for ages!

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I have the advantage that the engine is out (you can see in my TD5 rebuild thread) it's not so bad in the bonnet and under the seat but a pain to route it round the gearbox, I will give it a go and then possibly take out the gearbox cover inside to be sure i dont trap the wires or put them where they might chafe on something.
Watch this space.

https://www.landyzone.co.uk/land-rover/at-last-the-big-td5-job.349420/

tom1979 said:

You can add AC easily too now if you want!

Would be interesting to hear how long it takes you to change the loom! I’ve been putting it off for ages!

Click to expand...

Well I bit the bullet and did it today.
My advice would be if you dont have a very good reason to do it then dont.
I have the engine out and I took the transmission cover off and the cubby box and central panel, and it wasn't easy, took me about 5 or 6 hours and it is really awkward, you need to be sure the looms are supported correctly and dont run on anything. I dont think it would be possible with the transmission cover still in.
I just hope the loom is a good one.

raywin said:

Well I bit the bullet and did it today.
My advice would be if you dont have a very good reason to do it then dont.
I have the engine out and I took the transmission cover off and the cubby box and central panel, and it wasn't easy, took me about 5 or 6 hours and it is really awkward, you need to be sure the looms are supported correctly and dont run on anything. I dont think it would be possible with the transmission cover still in.
I just hope the loom is a good one.

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That’s about 5 or 6 times longer than I thought!! I’m only doing the engine loom, none of that goes through the cubby box does it?

tom1979 said:

That’s about 5 or 6 times longer than I thought!! I’m only doing the engine loom, none of that goes through the cubby box does it?

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No it doesn't go through there, but to open up some access to the space under the driver's seat where the cable come in you need access (it's right over the transmission) and the loom is fastened to brackets under the transmission cover for support.
Cable has a large rubber grommet on it which is fun to thread in there.

By the way we are talking engine loom here not injector loom.

raywin said:

By the way we are talking engine loom here not injector loom.

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Yeah i realised that When I looked at mine there didn’t look like enough of it to run all that way.

tom1979 said:

Yeah i realised that When I looked at mine there didn’t look like enough of it to run all that way.

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Injector loom is pretty easy done it before, just take care pulling the spring retaining clips off the the injector plugs, use decent snipe nosed pliers and dont drop them into the engine.

raywin said:

Injector loom is pretty easy done it before, just take care pulling the spring retaining clips off the the injector plugs, use decent snipe nosed pliers and dont drop them into the engine.

Click to expand...

I wasn’t talking about the injector loom