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MG MGB Technical - Wiring loom

Does anyone know of a more up to date version of the standard wiring loom?

More fuses and relays?

Just a thought before I buy a standard one.

Colin
Colin Parkinson

Hi Colin

I have just received my Advance Auto Wire harness. It has:
High beam
Low beam
Horn
Cooling fan
fuel pump
Ignition
Starter
I feel I will need to add another for the HRW.


I ordered it in July and it only arrived last week but the quality look good with heavier duty cables yhan stock.

Cheers
Tony
Tony Brough

Tony,
Looking at the Advance auto web site it appears to be a small loom you cut into the original. You still end up with all the dodgy bullet connectors.
A J Dee

AJ

It is a complete harness and does not use any of the original other than bulb fitments.

The routing and design keep the use of bullet connections to a minimum. For example the headlight wiring is direct from the board to the headlights without a break.
Tony Brough

Hi Tony, I have had a look at that from Advance, but am a little confused.
Does this come as a complete loom, taped up ready to fit, or do you have to tape it and fix connectors?

Have you fitted yours yet?
Where does the power block mount and do you have any pictures?


Oh and price???

Thanks

Colin
Colin Parkinson

Sounds good Tony.
A J Dee

I haven't started it yet. It is not bound or wrapped. My intention is to tape it up when I have tested it all works.

I have attached a pic of how it comes out of the box.

Mike Howlett has fitted one in his V8 and is happy with the outcome.

I will upload a picture of wher Mike mounted his.

I first started looking at this about 2 years ago when the exchange rate was better!




Tony Brough

This where Mike mounted his, and I am likely to follow suit.


Tony Brough

I fitted my Advance Auto harness way back in 2007 or thereabouts. The quality of the cabling and fixtures is top notch and it has performed brilliantly ever since. If you are a purist, the cable colours conform to the normal standard, but don't look the same as the old wiring, and they use bright yellow for main power cables. The gauge of many wires is larger than standard and the toughness of the insulation is remarkable.

There is a lot of work involved in fitting it. The power board is fully wired up with fuses and relays as you can see in the pictures, but all the wires are way too long and all need shortening and terminals soldered on. Fortunately I enjoy that sort of work. I have lots of wire left over.

On my V8 the fuel injection harness includes a fuel pump relay, so I was able to use that relay on the power board for the rear window heater. I seem to recall having to slightly shorten the depth of the cardboard glove box to get the board mounted there. In fact the glove box liner is no longer fixed at all, just wedged in place. It can be removed in seconds for access, and has never fallen out even though it is often used for storage of sat nav, etc.

In my photo that Tony posted, the shiny box below the power board houses the ECU for the fuel injection.
Mike Howlett

Looks like alot of money for only half a job!

I might as well build my own loom, or buy a new one and modify it to suit.

Nearly $600 + shipping and maybe duty!
Colin Parkinson

Colin, I agree build your own. If you like the idea of a relays/fuse board, they are available from Autosparks and Vehicle Wiring Products. The also sell "thin wall" wire which has the same current carrying capacity but with thin, more flexible insulation. The colours are a close match too.
Allan Reeling

Progressing 1 stage further, is there a list of how the looms developed?
What extra wires were put in and when?
It would probably pay me to get the latest rubber bumper loom with all the options, and then modify to fit my chrome bumper roadster?

Or am I missing something?
Colin Parkinson

Why would you want to fit the latest harness, pay more, and have loads of unused wires? Depending on the year of your car it could be counter-productive as component requirements changed as well, and the some of the harnesses gained plugs and sockets which your CB won't have. About the only thing that might be helpful is the 1980 body harness to the rear which had a fog-light wire.

You would have to look at the circuit diagrams year by year to see how they developed - have fun :o) But to help you see here http://www.mgb-stuff.org.uk/electricstext2.htm#colour and scroll down to the table, which lists the colours and circuits for each iteration.

paulh4

This thread was discussed between 05/11/2017 and 08/11/2017

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