2CV dashboard indicator LED lights – prototype

When fitting the proof of concept LED dashboard indicator light I had found the 7mm PVC tubing wasn’t a firm enough fit to hold the LED in place in the bezel.  I found some 5mm ID – 8mm OD tubing advertised an bought a short length.

When the tubing arrived it was immediately obvious that the 8mm OD claim was somewhat of an underestimate: it actually measured 9.5mm.

By cutting a section out of the circumference of the tube I was able to reduce the outside diameter to fir the bezel.  However, this also reduced the inside diameter by the same amount and, as this had started at 5mm, it meant that there wasn’t room for the LED.

At this point a plan B presented itself:  I could use this larger tubing as a stopper behind the LED to prevent it pulling out.  After some experimentation I found that cutting a V shaped notch in the tube would effectively create a tapered grommet.

2CV dashboard indicator LED with rubber grommets

The compressibility of the rubber combined with the taper created a very effective seal behind the LED.

2CV dashboard indicaotr LED and bezel assembly

With the light in place I trimmed down the leads to the right size for the light barrels and attached some male spade connectors.  Due to the thin wire used for the LEDs there wasn’t much for the crimp connectors to grip so I used the crimp to hold the insulation and soldered the bare wire to the connector blades.

A side-by-side comparison with the originals shows they look very similar and should fit into the dashboard with no issues.

Front comparison of original and LED 2CV dashboard indicator LEDs

Side comparison of original and LED 2CV dashboard indicator LEDs

When doing a test with a battery the colour of the connectors became an issue.  The insulating sleeves are red plastic (denoting the size of the connector) so the only indication of the polarity was the wire that by now was mostly hidden in the light barrel.  Given the polarity of a diode is what makes it functional I coloured in the negative connector with a permanent marker to make fitting easier.

Testing a completed 2CV dashboard indicator LED

The final prototype was now complete and consisted of an LED crimped and soldered to two spade connectors, a 7mm clear PVC grommet and a C shaped rubber grommet.

2CV dashboard indicator LED parts

Other posts in this series

  1. Deconstructing 2CV dashboard indicator lights
  2. 2CV dashboard indicator LED lights proof of concept
  3. 2CV dashboard indicator LED lights prototype
  4. 2CV dashboard indicator LED lights
  5. 2CV dashboard indicator LED lights – fitting