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In the British car hobby, we are always buying parts. Parts to fix what’s broken, parts to refresh older parts showing signs of wear, parts for better handling, parts to go faster, parts for bling, etc. This article is something completely different. How about parts to help the guy driving behind you? One of the nicest things you can do for someone you have probably never met, and at the same time take care of your TRiumph, is to install LED tail/brake lights. LED kits are available that will greatly improve the visibility of your TRiumph at night and under braking conditions. Sound like a bad investment? Not really, read on. Assisting the driver behind you just might prevent him/her from rear ending your beloved classic.

The existing tail light/brake light combination of the TR4/4A/5/250 uses a double filament (1157) bulb that puts out a minimal amount of light even under the best of conditions. Above this lamp is a single filament (1156) bulb for turn signals, that does not put out any more light. Using an LED replacement can reduce the energy consumption of the lights by as much as 80% and increase the light output by three or four times the original lamps. LED replacements produce visible light faster than incandescent bulbs and dramatically increase the light output. Both helping the driver behind you but at the same time decreasing the likelihood of damage to your car.

There are some very inexpensive (with corresponding levels of light output) solutions that are easy to replace. These are direct replacements of an LED bulb for the 1156/1157 bulbs currently in the car. Many of these feature 25-35 LEDs on the single bulb but only a few of these are on the rearmost portion of the bulb. Many are on the sides of the bulb and in the TR4/4A/5/250 the tail light frame would block most of the light from these LEDs.

In addition to the replacement bulbs, some manufacturers provide a circuit board type unit with multiple LEDs mounted on the circuit board. The one I selected was from Classic Auto LEDs and while more expensive, seemed to have the brightest light and required no permanent changes to the car. It features a total of 192 super bright LEDs, is a direct replacement without cutting any wiring (unplug bullets, plug in bullets from new LED units), and separate ground wires to eliminate the dodgy original ground via the bulb holder contacting the body (Photo 1). 

In order to explain the process, I will list the steps, following which I will give any explanation or caveats.

1. Remove the three machine screws holding the lens to the housing.

2. Remove the two bulbs.

3. From inside the trunk locate the wiring to the tail lights and remove the bullet to the tail light from the connector.

4. Remove the rubber boot from around the bulb holder and pull the wires and bullets through the hole(s) in the boot.

5. The wires can now be pushed through the housing so that the contact plate and spring come out the rear through the bulb holder (Photos 2 and 3). Note: in Photo 3, the socket does not have to be removed. It is only shown here for illustration purposes.

For each of the above steps, note the following details:

1. Note the top and bottom screws are a different length from the centre screw. The lens is in two parts that interlock. Many lenses that I have disassembled come off as a single lens. However, a few, including this one, came off in two pieces. Be careful you don’t drop and break something.

2. Apply pressure inward and twist the bulb to remove. The top bulb (flasher) is a single filament bulb and you will notice a single contact at the base. The bottom bulb (lights and brakes) is a double filament bulb and you will notice two contacts at the base. Both bulbs are grounded through contact with the bulb holder.

3. Take note of the wire colours in the event yours have been changed in the past. Turn signals will be green with a coloured tracer – red tracer for the left turn signal and white tracer for the right turn signal. The brake lights use the red wires. The tail lights normally use green wire with a purple tracer.

4. The bullets may be a tight fit through the holes in the boot. Depending on how much effort you wish to put into preserving the bullets and boots, you may need to make a decision. If you want to preserve the boot and the bullets, keep trying. If not, you can make the process easier by either de-soldering or cutting the bullet from the wire and pulling the wire through the boot or cutting the boot around the wire to create a larger opening. You cannot reuse the boot as is anyway. The new LED lights have one additional wire (ground) and that wire has an eyelet connector, so the wires cannot fit through the boot without some minor surgery.

5. If you plan to keep the existing unit, be careful securing the contact plate, it is very fragile and sometimes brittle.

Now let’s start the install. As earlier, I will list the steps followed by the caveats.

1. Test fit the circuit boards.

2. Pull the two wires for the turn signal circuit board through the upper socket and into the boot. Remove one of the nuts securing the tail lamp housing to the body (inside the boot), attach the eyelet for the ground wire onto the stud, and tighten the nut back into place.

3. Apply the Silicone Sealant and press the circuit board into place (Photo 4).

4. Pull the three wires for the tail light circuit board through the lower socket and into the boot. Remove one of the nuts securing the tail lamp housing to the body (inside the boot), attach the eyelet for the ground wire onto the stud, and tighten the nut back into place.

5. Apply the Silicone Sealant, and press the circuit board into place.

6. Gently press the gasket into place around the circuit boards.

7. Plug the wires from the new LEDs into the connectors in the boot.

8. Wrap Silicone Fusion Tape (Home Depot) around the socket and the wires to make a water tight seal.

9. Carefully place the lens over the gasket, insert the three screws, and tighten the lens to the housing.

For each of the above steps, note the following details:

1. The turn signal area is bordered on the sides by two vertical ridges and on the bottom by a horizontal base (at the centre screw location). The bottom base will support the circuit board. On both of my units the circuit board was a tight fit at the vertical ridges so I marked the location and filed 1/16” off each edge.

2. It is important that you connect the ground wire before attaching the circuit board for the turn signal as the circuit board will block access to the fastener inside the tail lamp housing.

3. Apply a bead of silicone sealant to the tail light housing just below the top screw hole, inboard of each vertical raised edge, and just above the horizontal raised edge.

4. Again, it is important that you connect the ground wire before attaching the circuit board for the tail light as the circuit board will block access to the fastener inside the tail lamp housing.

5. Apply a bead of silicone sealant to the tail light housing just above the lower screw hole, inboard of each vertical raised edge, and just below the raised text on the housing (and above the recessed area housing the socket). (Photo 5)

Since most flasher units for our cars are designed to work with incandescent bulbs, you may need to replace your flasher relay with one designed for LEDs. Normal flasher relays require at least two incandescent bulbs in order to work properly as LEDs draw as little as .25 watt compared to the 4 watts of the incandescent system. I used the CEC EF33RL relay shown in Photo 10. Initially, with only one side installed, the signal lights flashed normally but only generated one click. After the relay for LEDs was installed, the lights flashed normally and generated clicking sounds as expected.

Supplies used for this task included:

1. Permatex Clear Silicone, an adhesive sealant to hold the circuit boards to the tail lamp housing,

2. 3M Super 33+ Vinyl Electrical tape, to cover any exposed wires or connectors, and

3. Gardner Bender Silicone Fusion Tape, to make a water tight seal around connectors. (Photo 11)

Another upgrade you might consider is to replace the three individual bullet connector sleeves shown in Photo 9 with a single “Isolated Triple Bullet Snap Connector Sleeve” (Photo 12). Product C333 available from British Wiring. Unlike many bullet connector sleeves in our cars that are “common”, in that all wires inserted are interconnected; this connector features three independent connections so turn signal, tail lamp, and brake light wires all remain separated from one another.

I am confident that those of you who have followed me at night, now see this TR4 “in a better light”.)