I know this a fiddly part of the build, and it’s also an area where I think Caterham’s instructions from either manual are at best described as disappointing. 

Part of the problem is there are a few IVA relevant points that also need to be addressed during the headlight install, and even the new manual doesn’t include one of them. Nor does the new manual highlight where the wires need to go.

Over the years, I have collected a large selection of heat shrink tubing and wire braiding from my previous  hobbies. I know I used to get my heat shrink from Maplin, but I am unsure where my braiding came from, either way you are going to have to find a new source.    

I have sourced a set of Caterham LED headlights, but my supplied kit was Caterham halogen headlights. After conversations with Caterham over LED headlights and IVA, it seems that presenting a car for IVA with LED light requires a certification of conformity, which I don’t have, so I decided to fit the halogen units until post IVA.  

I started by removing the headlamp unit from the headlamp bowl. There are a couple of screws at 5 and 7 o’clock to remove and the unit pulls apart. The LED unit has a couple of spade connections covered in heat shrink for the side light, so I decided to convert my halogen units to use the spade connections. This I did by cutting the red and black wire to the side light and soldered on two spade connections. Now the halogen unit is compatible with the wiring supplied for the LED unit. This step is only necessary if you have LED headlights and you are presenting the car for IVA yourself without the certification. 

I am not going to use the PVC tubing Caterham supplied for wiring protection, so I removed that. Next, I laid out all the components, headlight, front indicator and headlamp mount and assembled them loosely in the correct order. I apologise for my photos here, because they are based on an alternative approach to keeping the wiring tidy. However, I decided I didn’t like the end-result, so I changed the method, but didn’t update the photos at this step.

To replace the PVC tubing I used the following 

  • 60mm of 5mm Black Braiding
  • 100mm of 10mm Black Braiding 
  • 20mm of 7mm heat shrink
  • 60mm of 7mm heat shrink
  • 30mm of 13mm heat shrink
  • 300mm of 7mm heat shrink

When you cut the braiding you will need to melt the ends to prevent frying, I do this with a match.

Slide the 60mm of 5mm braid onto the indicator wires. Don’t forget you can compress the braid to get the earth ring through.  Next the 20mm of 7mm heat shrink is slid over the indicator wire and the braid, and up to the end of the braid. This heat shrink is going to prevent the braid from frying and make the end as neat as possible. This can be heated now. I use a heat gun because to prevent damage. 

I slid the 100mm of 10mm braid over the headlight wiring next, but I didn’t slide the braiding into the headlight at the moment. I took the indicator earth wire (the black one) back through the 10mm braid and into the headlight unit. It needs to pass through the headlight unit seal. Don’t forget to attach the indicator earth to the headlight bowl. Now the braid can now be pushed into the headlight fixing.

The 30mm or 13mm heat shrink is then slid over the headlight wiring, green indicator wire and over both the braiding.  Don’t heat this yet.  Next slid the 60mm of 7mm heat shrink over the headlight wiring and the green indicator wire, up to the braiding. Finally make sure the grommet is slid over the wires. Again don’t heat this yet.

If you want to fit the grommet (and not glue it) don’t use the kit supplied item, use a thin walled flexible grommet. See my upper wishbone post.

Now the fiddly bit: Slide the wires into / through the headlight mount, one by one.  Sometimes the connection gets stuck, in which case you can use a pick to just ease the connector through the mount, one by one, then once they are all through the mount I pulled them bit by bit, until I had the wires where I want them. 

Ready to heat

The end of the 60mm of 7mm heat shrink should also go into the headlight mount with the wires. Finally, with the wires and heat shrink in position squeeze the flexible thin walled grommet into place. This is very tight, but doable. I used the edge of a plastic trim level, from a plastic trim level kit and it took me about 5 – 10 mins to get it seated properly, so be patient. 

Desired finish

Now I heated the heat shrink to complete the process. 

The last step of the headlight unit assembly is to apply the 300mm of 7mm heat shrink to the wires coming out from the head light mount. I suppose you could use the supplied PVC tubing. It’s tight to get all the wires down such a long length of heat shrink, so start with the shortest wires first, so you have some slack when it gets tight to pass the last wire through. I made sure the heat shrink was pushed into the mount before heating it.

If you followed my upper wishbone post, you will have the IVA grommet in place in the chassis and you will have already tested the headlight mount fits the chassis. If not,  then you may need to adjust the mount to get the holes to align.  

Remove the upper wishbone mounting bolt, then pass the wires through the IVA grommet, and refit the bolt. The wires push the mount towards the wishbone, so a bit of masking take protection can prevent any damage. Tighten the upper wishbone bolt to the specified 47Nm and you’re done (apart from repeating the process all again on the other side).

Refitting the headlight unit is a simple task. I put a small tie wrap at the top of the headlight seal to secure the wiring. My modification to allow the LED units to be retro fitted post IVA means, I needed some more 7mm heat shrink to protect the side light connections (as per the original Caterham supplied LED unit wiring). Then I reconnected the headlight bulb wiring and refitted the lens to the bowl.

Headlight installed

Just had to repeat the process on the other side, to complete the job.

Here are a few photos of an alternative approach, using just heat shrink and a Y-shaped heat shrink boot from RS components (https://uk.rs-online.com/web/) Part No. 2181426

Tools Used  

  • Matches
  • Soldering Iron
  • Side cutters
  • 1/4 Ratchet
  • 8mm 1/4 Socket
  • Pick
  • Philips screw driver
  • 3/8 Ratchet
  • 3/8 Extension
  • 17mm 3/8 Socket
  • 17mm Combination spanner
  • Scissors
  • Plastic trim lever
  • Heat gun