Heater Control Lighting
The heater control lights aren't very well lit and colour coding with LEDs isn't ideal. Let's check out the problems and alternatives.
Should The Heater Markers Light Up?
Yes they should but quite often the bulb blows and people question whether they illuminated before.
Where Is The Bulb?
While not immediately obvious, the bulb is actually fitted inderneath the safety cluster triangle.
Follow this guide to remove the triangle from the dash so you can access the bulb.
You will find a single 509T twist fit bulb in the centre. Replace with another bulb and test.
Can I Fit An LED Instead?
You can but don't expect it to look very good, this is because of
the light guide used to distrube light around the heater markers.
The Problem With Light Guides
The initial problem is that the light guide collects light from the side of the bulb.
Standard bulbs illuminate in a very wide beam so light is collected with no problems.
A standard LED illuminates forward so the light guide has problems collecting light.
This means that the collected light is only a fraction of that produced by the LED.
Light guides are very inefficient at carrying light around corners,you can lose
30% of the light through a 90 degree bend, the light guide has two each side.
The final deflection that lights the heater controls will only use about 20% of what it is given.
Because of the pick up point of the light guide and it's inefficiency to carry light,
you can only expect to see about 2% of the light created by the LED.
So What Is The Solution?
You have a few option to take a look at:
Altered LED Designs
This is a standard LED, they often produce a narrow beam to increase the output.
When used, they usually create a bright spot with no lighting at the side.
The new style flat top LEDs create a slightly wider beam that isn't affected by the done lens.
They create a larger bright spot with no side lighting.
The heater control light guide picks up light from 2 opposite sides so the above LEDs
would not be suitable for usage in that area although some lighting may occur.
What we need is an LED that will emit some side lighting,
currently that only leaves us with the new 'inverted cone' design.
Although the inverted cone design will give better side lighting, it's not perfect.
To get the best from an LED you have to modify it yourself.
If you got a standard or flat top LED and cut a V shaped valley into the top
and then glued a tiny bit of tin foil into the V, it would reflect all the light sideways.
The EL Wire Method
This is what we will be using to back light the heater controls.
It is often called neon rope but is actually Electroluminescent wire.
This particular one was purchased on Ebay for £10, it's 5ft long and 2.3mm wide.
We need to get to the light guide so remove the centre console,
that how2 can be found here.
With the centre console off, spin it over to reveal the light guide cover.
This is the light guide header, this is where the bulb sits that normally lights the controls.
At the botton is a tiny Torx6 screw, this can be undone with pliers instead.
The light guide and cover should now pull free from the centre console.
Flip open the tabs at the top and remove the light guide, run a bead of impact adhesive
around the inside of the light guide cover... (don't use superglue)
and stick the wire into the cover. Selotape the wire in place while it dries.
When it has dried, add another bead of glue and do another lap with the wire.
Hold it all in place with selotape for about 20 minutes until it has dried.
Reassemble the modified lightguide cover back into the centre console,
remember to replace the tiny screw at the bottom.
Run the wire down the side of the centre console and to the cigarette lighter socket.
Reattach the centre console securely and test the new lighting by turning the car on.
Alternatively you could wire it elsewhere but in this case it was the easiest option.
The Double Horizontal LED Method
Remove the light guide as show above. The picture shows the light pick up point.
Take a very fine saw and cut the light pick up point off. Polish the ends with a fine file.
You can also use fine wet and dry paper and also a lighter if you are careful.
This is called flame polishing. Don't keep the flame on it too long as it can bubble the plastic.
I used 2 small sections of 3mm ID silicone hose and pushed one on each end.
Standard 5mm LEDs push nicely into the tube, butt them up against the tube inside.
Using the correct resistor and wiring method you can see that the illumination is far superior.
The resistor you use will depend on how you wire the LEDs.
As a general value, 470 Ohm will work with most LEDs in singles.
330 Ohm will work best if the LEDs are wired in series.
270 Ohm will work best with LEDs wired in parallel.
The best thing to do is Google search the phrase LED resistor calculator.
Fill in the details about the main voltage and your LED specs and it will tell you
which resistor you require depending on the way you wire them together.