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Front indicator upgrade, Just add Lightness LEDs and clear lens

Updated: Jan 2

At the time I ordered my Caterham 7 I didn't realize it was possible to purchase the car with a clear lens pack, and so my car was delivered with the standard Orange lenses over each of the indicators. Not an issue, but I very quickly decided I'd start upgrading to a clear lens setup as soon as possible. I didn't feel the Orange colouring sat well with the body colour plus the clear lens would certainly complement the silver decals.

While swapping out the Orange lens it also made sense to consider a bulb upgrade, after all, I had to replace the original clear bulbs with amber bulbs. After looking around online I decided to upgrade using the Just Add Lightness bulbs and light clusters where appropriate. The upgrade process isn't cheap, so I decided to undertake the process gradually, first on the list was the front indicators.

Why change to LED? Well according to Just Add Lightness there are a couple of reasons.

  • Safety

  • Efficiency

  • Endurance

Efficiency and Endurance are pretty obvious, the LED consuming less power for comparable if not greater illumination, plus its ability to maintain operation through repetitive cycles of vibration from general motoring.

The Safety aspect is one for greater discussion. Just Add Lightness (JAL) state in their marketing an LED lights up 0.2 seconds faster than an incandescent bulb, which at 75 mph equates to 21 feet travelled. In the case of a brake light, the extra distance might make a considerable difference when avoiding an accident. I appreciate at this time I'm fitting front indicators, which are the cheapest option, nevertheless, it might be an interesting hypothesis to test. The aforementioned marketing statements can be found here;

Packing of the JAL front indicator LED bulbs is simple being supplied in an unbranded cardboard box and bubble wrapped, as shown below.

Given the name, Just Add Lightness, I decided to see if a bulb was in fact lighter than an original bulb supplied by Caterham Cars. The JAL LED front indicator bulb weighed 12 grams, in comparison the standard bulb which came in at 7 grams, so 5 grams heavier. 12 grams is the same as a mint humbug and Starbust, sorry I only had the one Starburst left.

I purchased a set of genuine Caterham Cars clear lenses from Demon Tweeks. My choice to source from Demon Tweeks was one of speed and ease, plus the cost was the same. (£4.12 / CATFRL425L)

(£4.12 / FRL425L)

A quick comparison of the two lens styles.

Fitting, unfortunately, wasn't as smooth as expected.

The first step was to remove the two retaining screws which hold the lens in place, then remove the lens followed by a push and twist on the existing bulb, the bulb then pops out. Fitment of the new JAL LED bulb is then the reverse, and of course swapping for the new clear lens. Unfortunately, I found the bulb loose in the holder and as such the electrical contact was unreliable and only intermittently worked. Both indicator assemblies with both LED bulbs appeared to suffer the same issue, so it seemed pretty consistent. Not a good start.

Luckily I had a spare but broken indicator assembly, the plastic screw thread had split on the assembly, it was in sufficient working order to assess the situation with the poor connection and devise a solution.

Given the bulb felt loose in the holder I initially thought it was the ground which was the poor connection, this turned out to be incorrect. I believe the problem is due to the JAL LED bulb and side retaining lugs being very slightly smaller than the original and as such the rear terminal which is sprung loaded doesn't make reliable contact and also allows the bulb to feel loose in the holder. The sprung loaded rear terminal and plate helps to press the side tabs into there retained position.

I experimented on the spare unit and found if I used a pair of pliers to gently pull the rear terminal through the sprung loaded plate it would reduce the clearance and hence make a reliable connection, plus improved the bulb's stability within the holder, although it's still not as tight as the original bulb.

Caterham 7 blog LED indicator light just add lightness
Gently pulling the rear terminal through by about 3mm

I carefully used the same technique on both indicator assemblies and subsequently managed to complete the install of the JAL front LED bulbs. Check out the install video below.

Having successfully installed the LED bulbs it was time to take a look at the performance. Between completing each indicator I recorded some comparison video footage at 120 fps.

The first video below shows a comparison in real-time, the right indicator with a clear lens is using the Just Add Lightness LED bulb whilst the left is using the standard Orange lens and the standard incandescent bulb.

It's pretty clear from the video the LED bulb is brighter causing a greater halo effect on the recording camera lens, it was also very clear to the naked eye. There is a very slight speed difference noticeable when played in real-time, you can spot the filament gradually increasing it's light emission. This becomes more noticeable when each frame is stepped through.

To help illustrate the difference the same footage has been slowed down in the following video. Using slow motion the difference in response time becomes clear.

For me the above video truly validates the improvement in brilliance but also responsiveness. I appreciate it's less critical on the front indicators, increased light level certainly helps, but there's negligible safety benefit with regards improved response time of an indicator. It does however demonstrate the improvement available when using the same technology for the rear light cluster which includes the brake lights. The importance of optimising the 7's brake light system when it's placed so low on the road, and considering how vulnerable you are in such a small car makes for a simple decision.

It's a must upgrade for all.

Height is important too, and as many Lotus 7 club members have pointed out, a high level brake light is critical, especially if you find yourself being tailgated by White van man!

An LED high level brake light modification is also on the cards then!


JAL LED Indicator Bulb


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