Triumph TR3 drawing


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Converting a riumph to halogen headlamps


Halogen lamps throw out a lot more light than the Triumph's original tungsten filament headlamps. This article is specific for the TR2-3B but can easily be adapted to outer Triumphs.


Converting to same wattage Halogen lamps

Converting to Halogen headlamps with the same high and low beam power ratting (Watts) is very easy. It is simply a matter of removing your old tungsten filament headlamps, installing new halogen headlamps, and plugging the headlamp connectors back in. You will get a very noticeable increase of light to drive by. Since you are not changing the power that your stock wiring harness caries you do not need to modify it. However to get the best light out of your new headlamps it would be a good time to check over your headlamp wiring connections.

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Converting to higher wattage halogen headlamps

High power halogen lamps exceed the power handling capabilities of a stock TR3 wire harness and can cause damage to the harness and switches. You should rewire part of your headlamp harness and add a relay if you are planning to install high power halogen headlamps.

High power halogen headlamps are normally labeled as high power on the box (if in doubt ask your sales person). The high power lamps usually have a low beam similar in power to the standard power halogen and tungsten filament lamps. The high power is usually reserved for the high beams. To safely use this kind of headlamp you need to put a relay in the high beam circuit to handle the additional power draw. You would leave the low beam circuit alone in this application.

There are some special high power lamps that are available that have high output on both high and low beams. This would require a relay on both the high beam circuit and the low beam circuit. I recommend against getting these lamps. You do not want to blind oncoming traffic when they are hurling their cars in your direction.

You will need to go out and purchase a relay if one did not come with the headlamps. Lucas makes a relay that is a rectangular metal can that works very well for this application. There is often a diagram of the relay's electrical connections etched on the side to tell you how to wire the relay.

Mount the relay on the upper kick panel or inside bulkhead above and near the foot dimmer switch.

You can get your electricity from the amp meter on the side that has the brown wire with a white stripe. Or you can get it directly from the battery or a fuse box connection with a solid brown wire.

You will want to connect a line fuse between where you pick up the electricity and the relay. The wire between the amp meter and the fuse should be brown with white stripe. If you are taking it from the battery it should be solid brown. The colour of the insulation between the fuse and relay should be solid blue. Depending upon what kind of wire measuring system you are using the wires should be #12 AWG, or 44 strand.

The stock wire harness has two blue with white stripe wires going from the foot switch to the bright beams of the headlamps.

You will use the foot switch to activate the relay and provide power to the high powered headlamps.

Looking at your relay there should be four connectors. They may have labels like S1, S2, R1, R2 or there may be a picture etched with corresponding connector designations. The connectors labeled S1 & S2 or shown on the diagram as a coil are the low power connections to the internal solenoid that activates the high power relay contacts.

Place a black wire on one of the S connectors and route it to a good body ground. The other S terminal gets connected to the high beam connection on the dimmer foot switch. It doesn't matter which of the S or solenoid terminals is which. This circuit now uses the dimmer foot switch to actuate the relay.

Now, the brown wire to line fuse to blue wire goes to one of the R or relay contact terminals. Once again it doesn't matter which. Finally connect the two 44 strand (#12 AWG) blue with white stripe wires that were attached to the dimmer switch to the other R terminal of the relay.

And that is all there is to it. If I ever go to high power high beam headlamps that is how I would wire the connections.

The fuse size depends upon the power your high beam draws so there is no firm number that I can provide. Since you have two high beam lamps divide two times the wattage of the high beam by 12 then add 25% as a fudge factor. Choose a fuse that is the closest higher current rating.

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Dim headlamps

Dim headlamps are often caused by oxidized or loose harness wiring. Connections will oxidize over time creating increased resistance. This will make your headlamps dimmer. So when you replace your headlamps it is a good idea to clean your wire connections and make sure that the headlamp harness is in good condition.

The connectors that plug into the back of your headlamps are each part of a small three wire sub harness. If this sub harness has degraded new ones are readily available.

The black wire will go to a body ground connection just behind the front valance on each side. Make sure that all the connections are clean, including the connection between the ground connector and the metal of the bulkhead. A bad or high resistance ground connection is the most common cause of very dim headlamps. New Lucas ground connectors are readily available.

The blue/white and blue/red wires each go to connectors near the front valance. Check to make sure that the bullet connectors and the inside metal of the connectors are clean.

Check the rubber gaskets where the wires pass through the headlamp bucket. Replace with new ones if the originals have deteriorated or are missing. These gaskets protect the insulation from abrasions that can cause shorts in your headlamp wiring.

Check the connections to your hi-lo dimmer foot switch. It is probably a good idea to remove the foot switch, clean up the area and the connections. Make sure that the insulators around the connections are in place and in good condition to prevent shorts.

Open your instrument panel and check the connections to your headlamp switch. The wire going to the foot switch is the blue one. Once again you want a clean firm connection.

This should provide you with bright headlamps. Don't forget to clean the head lamp lenses whenever you clean the windscreen. Dirt over the lenses can block out a lot of light and cause the headlamps to run warmer.

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