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MG TD TF 1500 - Adding turn signals to TD

Everyone was such a help on my accessory socket question. How about this one? Is there a tech bulletin for adding turn flashers to TD. My new, (actually I bought it 18 years ago), wiring harness has the leads for the flashers but where should I mount the control box and the flasher relay? Am I right in assuming the the control box is mounted on the back of the tool box.

Thanks again for the help.

Greg Armstrong
Oshkosh, WI


I will be watching this post with interest as I am currently doing the same thing. My harness is set up for turn signals and the front wing lights have the new internals. The dash has been wired using the workshop manual and a little imagination. I don't have a turn signal warning light yet but I assume that it is a must and will find a place for it. In other postings I believe that you are right that the control box is fastened to the back of the tool box (under the dash) and I am pretty sure that the turn signal switch is mounted behind the dash.

After watching traffice trying to figure out what someone was doing with their arm out the window signalling to make a turn I believe that it is manadatory today. (The person was actually sitting at a traffic light waiting to turn left and she was signalling for a right hand turn!!!!) Young (and not so young) drivers are not alert to hand signals anymore so a good set of bright turn signals appears to be a great move.

Brian Smith

Hi Greg;

I installed the Moss turn signal box several years ago and it works ok part of time. The right turn signal works all of the time and the left turn signal works some times if it is warm enough out. One of the relays (Bosch not Lucas) inside the box is temperature sensative and I have had it apart to try cleaning and adjusting several times without success. One of these days I suppose that I should call Moss to see if they carry replacement relays, Ha Ha. Remember that the brake lights also work through this box if it is installed so one needs to keep an eye on things.

As far as the installation of the box,I installed it in the engine compartment on the front side of the left verticle mount for the tub attachmentto the frame. It was installed there because the Moss harness that I purchased did not provide sufficient wire length to install it inside the cabin area. The car has been driven through several heavy rain storms (read that Florida) and the box has not had a water problem. If possible however I would mount it on the back of the tool box. The only problem with that is accessability if you too run into relay problems. If you happen to have a tunnel mounted heater installed that will compound the accessability problem.

The next question is the switch. I could not find the correct turn signal switch at the time so I used a single pole, double throw switch mounted in the correct spot. If you use this approach you do need a light as you forget to turn the switch off from time to time. I also installed a 12v beeper for the same reason. One or both can be used. I was told that the correct position for the optional turn signal light is in the center of the metal instrument cluster panel between the ammeter and the horn button. I chose not to damage the newly chromed and painted panel and installed the light below and between the speedometer and the tachometer. This way it is closer to line of sight when driving and is less obvious.

Good luck
Safety Fast

Dick McCutcheon

Hi Greg and Brian
I have a 52 TD ex US car. Fitted with turn signals. The front signals are fitted into the side lights and the rear are fitted as extra lights under the rear bumper (fender). The turn signal comes complete with the flasher relay unit and is fitted vertically under the dash just above the gear change lever. There is no indicator light fitted to my car. Hope this is of some help.
Mick Cook
M J Cook


There are three different relays in the turn signal circuit. One of them is the flasher relay, mounted either under the dash or near the passenger side horn. The other two relays are in an 8 terminal box mounted under the dash, on the back of the tool box. This box determines which brake light (and front side) filament flashes, based on the direction of the signal switch. It's an important piece of kit because it sits in the middle of the brake light circuit. It should be possible to make such a beast with common relays. You might want to check with Dave Dubois, he might have diagram for building something.

If you have the moss harness with signals, you will need the relay box, flasher relay, turn signal switch, and dual filament bulb holders for the side and rear lights to complete the stock setup.

Here's a picture of the 8 terminal box mounted, also an electical diagram that might simplify the layout. If the pictures are too small after you download them, let me know and I'll email them to you.

Good luck!
Evan Ford - TD 27621

Ok Evan, How did you know that I had a diagram, are you psychic or something? I do have a diagram that I drew up for building a relay assembly for the TD/TF/MGA turn signal relay. I can also come up with a list of materials for anyone who wants to make their own relay assembly instead of paying the ridiculous price for the ones on the market. I can also build a relay assembly for those who are electrically challenged. I get $50.00 for building the assembly, plus postage. Cheers - Dave
David DuBois


It was just a hunch! (You are the master of all things electrical!!) After seeing the great work you did on the brake relay setup, I figured you would be all over the relay assembly.

Evan Ford - TD 27621

See the archives for this discussion in detail a few months ago. I found a used Lucas relay box (traded for beer), used a Radio Shack toggle switch and miniature green light mounted under the dash edge to the right of the steering wheel. I mounted the relay box (as on a TF) on the right firewall, I think having to move the rectangular ID plate over or up. This is high and dry, and easy to work on (it will need it). As early TD's didn't come with turns, no installation is truly original, so I just put the box where it could be worked on.
George Butz

I went to an automotive recycler and looked at a pile if wrecked cars. Found a three set relay from a mid 90's Lincoln. This consisted of a base and three relays. One for high beam one for low beam and the third for the stop light circuit. All for $5.00.Worked perfectly.
Sandy Sanders
conrad sanders

This thread was discussed between 19/05/2004 and 21/05/2004

MG TD TF 1500 index

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