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MG TD TF 1500 - How t nstall a new Wiring Harnes

I had a short in my wiring from my head lights and it burnt some wiring, so I purchased a new harness for my TD. I need help to install the harness, does anyone have instructions or ideas on how to go about the installation. Any help would be appreciated.
Louis Levin
Modesto,CA

L.M. Levin

Here is a good start:

http://www.dbraun99.com/mgtd15470/Electrical/Electrical%20Restoration/Index.html

Tim
Timothy Burchfield

The grommet for the largest wiring hole in the bulkhead near the voltage regulator can't be assembled intact around the loom. It needs to be cut at the circumference with the cut located at the bottom of the hole. After spending ages attempting to fit it unmolested, I had to admit defeat. I also found that removing a circle of rubber of a suitable diameter from the flat section, rather than using slits, ensured a snug fit around the loom. Cheers
Peter TD 5801
P Hehir

Hi Louis

Haven’t talked to you in a while. Time flies and it’s been several years since I bought parts from you at your house. Do you still have the Singer? The harnesses are pretty straight forward. The hardest part will be getting the main through the big grommet in the firewall. The WSM has all the color codes and schematics. If you don’t have them let me know and I will scan them for you. Send me an email at the above link.

Look forward to hearing from you.

Bill Chasser
TD-4834

W A Chasser

The large grommet can be fitted without cutting. It needs to be placed on the loom close to the final position but not fit in the bulkhead until all of the wiring has passed through the opening...at which point a lipe can be worked over the sheet metal.
L E D LaVerne

battery charger

Here are a few ideas. And, it is not as difficult as it sounds at first.

Sit down with a wiring diagram and trace and mark all of the wiring. This helps ensure everything has good connectivity and also gives you an opportunity to check the terminations on the harness. Depending on your car, some may need to be changed (for example the coil) and some may be the wrong size (for example, ring terminals).

Get a friend to help so you can trace circuits as you wire more easily. Two heads are better than one (usually).

Take time and examine the existing wiring (especially the interior wiring), taking pictures and looking at the position of components such as the signal relay box and flasher mounting. Make sure the harness is routed so the body can be lifted if necessary.

Make sure you leave the dash connections sufficiently long that the dash can be moved for inspection and/or maintenance. If building or restoring the dash, make sure the gauges can be removed or installed. And make sure new dash lights (especially early dash) don't fowl the wood during installation. Some additional clearancing might be needed.

The dash harness is only a few wires. You can buy the correct wires (gauge and color code) and build your own dash harness. That makes it easier to route some of the wiring without tension.

Before starting, this is a good time to clean and check the voltage regulator screws and various internal points. Also the dynamo.

You will find it is helpful to buy the bullet terminal crimper. Crimping is usually better in an electrical system subject to vibration (soldering hardens the copper and creates a stress point). It also doesn
WHTroyer

Bill: Nice set of tips.

Louis. A few comments from me:

Not sure if you are doing a turn indicator harness or not. If so and your car is not a 53 then you could have some extra issues with getting all the wires through the large hole. On my 52 I had to have another hole, but maybe it was just me.

If you choose the fabric harness (original) the wires seem to be larger and therefore extra effort is sometimes required. I little Armorall helped me slide the some of the grommets on but don't let it saturate the wires.

You will find all sorts of much behind the pedal box when you route your rear wires. I would suggest first wrapping the bundle with painters tape before shoving it behind the box and then take the painters tape off after you get the harness in position. A must if you are using a fabric covered harness.
Christopher Couper

Outside of being oddly complex, the installation is fairly straight forward. There are some design flaws, mostly numerous connections, lack of fuses, long circuit runs,and return ground wires. I tin wires with solder before mounting them in grub screws. Di-electric grease in the connectors is a good idea. I have never had any issue with grommets needing to be cut. I use cloth branded harnesses, and have always been able to place them as they should be. With a wiring diagram and simple tools, the project is fairly straight forward. Wires are color coded, and the pattern is consistent throughout the car.
Be well,
David.
D. Sander

Re the grommet, my loom was an original cloth covered late 60's version and the grommet just couldn't be installed intact. The loom would barely fit through the hole without the grommet. I guess today's looms use thinner gauge wire. You may also want to consider a 20 pin quick disconnect plug behind the dash. See pic. It's never seen and makes access to, removal of and replacement of the dash a doddle. Cheers
Peter TD 5801

P Hehir

That disconnect is a good idea and the one you show looks period. :-)
Christopher Couper

The only concern I had was preventing the cloth covering from frizzing as I worked it through the holes. I covered those areas with plastic to protect it. I tinned the ends plus I put clear heat shrink on the ends to prevent fraying.
rich40701


The following is one concern with tinning copper wire used in a grub screw connection or crimped joint. Everyone has a different opinion and it is difficult for us to change our opinions ("a man hears what he wants to hear and disregards the rest"):

Soldered grub screw connections suffer from cold flow. You should not tin the wire used in a grub screw connection or crimped joint because the solder “creeps” under pressure. The wires will loosen under the screw or in the crimp and this creates a poorer connection (and allows water to enter the connection).

And, similar to pipe breakage in a moving house foundation, the copper wire can fracture within the area of cold flow.

If you do solder a crimped connection, crimp first and then solder. This is not possible when using a grub screw.

Expensive "pre-tinned" wire used to reduce corrosion in a grub screw connection actually has a thin layer of plating instead of solder.

This is why the factory did not recommend tinning the regulator wires.



WHTroyer

Great idea, Peter, but do you have any idea what those things cost on the retail electronics market? I simply used bullet connectors.
Lew Palmer

There are 3 x 15 pin connectors on Ebay for $24 each at present Lew. https://www.ebay.com/p/Bendix-15-Contact-Ms3112e-14-15py-Ms3116f-14-15sy-Gold-Multi-Pin-Connector-Set/2285038499?iid=153034982474. Some of the other stuff is pretty pricey though. Cheers
Peter TD 5801
P Hehir

Tim Burchfield: The web site you recommended does not come up, A message shows that "This page can't be found"
Thanks anyway.
Louis
L.M. Levin

Just a note to say thank you to everyone for their input on how to make the installation of the wiring harness easier.
Any one interested in coming to Modesto and helping me with this project? Beer and sandwiches provided, lol
Louia
L.M. Levin

Louis,

I just received my new wiring harness for my TF from Rhode Island Wiring this week and started labeling all the wires.

The instructions from RI Wiring are easy to understand and the quality of the work is outstanding. All the connections are excellent and whom ever did the solder work did it impeccably. The main harness also had all the vinyl coverings already installed that is usually missing from restorations. I highly recommend them.

http://www.riwire.com/


I bought a Brother PT 210 label maker that was on sale from Staples for 14.99. 60% off. My hand writing is like chicken scratches and this makes the job down the road much easier for me.

The main engine / dash harness was the most work and took the longest to complete labeling. Reading the wiring index, checking colors, typing, and labeling the wire took a while, but I know down the road it will pay off big time.

Frank
TF1414


Frank Cronin

This thread was discussed between 21/06/2018 and 24/06/2018

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.