TR2/3/3A Modified turn signals/brake lights on a 56

When I brought my TR3 out of hibernation in Spring 2019, I decided to upgrade the rear lights by modifying the existing outer lights to be both turn signal and brake lights. The only rear brake light on a 56 TR3 is in the center with the license plate lamp. I decided to upgrade the lights themselves with the Moss LED Tail Light Kit, part #143-810, and the existing center stop light with a suitable LED bulb from SuperBright LEDs. At the same time, I also upgraded the amber front turn bulbs with LEDs from SuperBright. Based on my research, I chose to use a Hopkins Vehicle Converter part #48845 to combine the turn signal and brake light circuits. The installation was straight forward though the Moss kit uses a red wire for the brake light and the car’s normal rear lamp is on a red wire. I could never get the system to work properly so that the center brake light did not blink when either side of the turn signals was activated. I might have been able to fix that with a diode, but I’m not an electrician, more evidence of that later. I returned the rear lights to their original wiring, but with new LED bulbs.
Fast forward to the Winter of 2019 as I am ending my driving season. I decided to try to modify the rear again. This time, I found a thread about using relays to combine the functions. I began a private discussion with Randall (TR3driver) that probably drove him crazy. He was very patient with me answering all my questions, just like he does on the forum every day. He sent me a schematic of how to wire the relays and where to interface the car wires. I mounted the relays (typical auto relays, 5 pin SPDT from online LED Store via Amazon https://www.amazon.com/ONLINE-LED-S...pin+relays&qid=1586614541&s=automotive&sr=1-3) on a piece of strap attached to one of the bolts holding the brake and clutch master cylinder box in place next to the pedals in the cockpit. I chose to use the correct color wires sourced from 4RCustomWire https://4rcustomswire.com/products/16-gauge-gxl-wire-individual-green-striped-color-and-size-options . I wrapped the wires in poly mesh sleeving, from McMaster-Carr https://www.mcmaster.com/9284k612, also Randall’s idea.
I had problems choosing the correct interface wires on the car. Randal, again, suggested using an old headlight as a “current limiter” when using the battery to trace circuits. For some of the circuits, I used a long pigtail and my ohm meter. I also had a problem understanding how the turn signal control head worked and interfaced with the flasher unit. The diagram in my Haynes Manual was useless. BCF regular, Marvin Gruber, who last restored this car, suggested the colored wire diagrams from Advanced Wire http://www.advanceautowire.com/tr24a.pdf. They gave me the knowledge I needed to finish the project.
But wait, there’s more! The right blinker circuit of the control head had a fault. After much more research on BCF, I gave in (gave up on tackling the removal and repair of the control head) and bought a SPDT on-off-on micro switch from StewMac https://www.stewmac.com/ who specializes in guitar making. I mounted the switch under the front edge of the dash.
All in all, I am very pleased with the results and want to give a shout out to BCF and Randall and Marvin for their help. This is a great Forum.

Very nice job on the wiring. I commend your effort. It takes a lot of time and patience to do neat wiring, Bravo !!! Frank

Nice work! Much neater than mine. Glad you got it working.

Great job. Also have a 56, and definitely feel a bit safer in the car with better front signals and all three rear lights. I bought hand-made LED rear lights from Bob Le Brocq in UK. Here is an article on his development of the bulbs if anyone is interested. http://www.ovtc.net/uploads/9/5/1/6/9516577/2nd_draft_article_on_lighting_improvemnets_all.pdf

Also a short video of them on my car. Since this was taken I removed the unit below plate. https://www.youtube.com/watch?v=3J_M3i0ceSs

Cheers, Mike

I've used Bob's LEDs in my car. They are terrific and Bob is very nice and helpful.

Absolutely Keith. I was a bit of a test case and Bob was great. Cheers, Mike

FWIW, I rolled my own, using a flat piece of aluminum and several "3 watt" red LED "stars" from eBay. I'm reasonably happy with the result (but plan to include more LEDs next time). It's a lot brighter than even the upgraded incandescent, and as bright or brighter than any other conversion I've seen.


In this (very brief) video, the one on the right is still a 2357, about 25% brighter than a 'normal' 1157.