I’ve been putting off the headlights for a while just because I wasn’t planning on driving at night and was preoccupied with getting more serious matters fixed. However, I registered for the Caffeine and Exotics event this coming weekend and was going to need functioning headlights as I’d be required to leave the house before sunrise. That led me to putting some time aside tonight to get the headlights wired up and I’m happy to say it was a lot less painful than I expected.

First off, the instructions from Caterham are not correct for a US car as the lights here use a two filament bulb whereas they are single filament in the UK. That means we end up with a red (hot) and brown (hot) wire while the UK gets a red (hot) and black (ground). You can see the problem here – no ground and both wires are hot in the US.

The correct method for US cars is to:

  1. Extend the red wire from the indicator to the 6-pin automotive connector in engine bay.
  2. Attach the brown wire to the small bulb in the headlight.
  3. Add a 3rd wire (black) as your ground from the turn indicator to the headlight bowl and secure with a terminal ring.
  4. The indicator on the front cycle wings then attaches into the automotive connector.

I didn’t do that – I just went with the UK way of wiring things up. What I ended up doing, and it works just fine, is to terminate the brown wire to the headlight bowl with a terminal ring and then extend the red wire to the 6-pin connector in the engine bay.

Why? Well, to start with I didn’t use the side indicators on the front cycle wings since I liked the look better without them. Jon (Caterham USA) told me many folks don’t use them and opt to leave them off so I wasn’t alone in this feeling. Second, the use of the indicator as a side light doesn’t measurably help in any way so why bother? Third, I’d already wired the car up according to the manual because months ago I didn’t know the manual was wrong, surprise surprise right?

After 30 minutes or so to open the headlight bowls, plug in the connectors, and check the lights – viola! Working lights and blinkers.

Working headlights

I then adjusted them as best I was able in the garage using the instructions in the manual and called it a night.


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