Incandescent lamps, even low power, produce much more heat than light. The plastic material is sensitive to it and can be deformed. As I didn’t wish to replace them with white LEDs (the main reason being that I wanted to keep the warm colour of the light), I designed a kind of tubular heat sink capable of evacuating the heat (which is still confined under the bonnets), but also and above all to distribute this heat over a larger surface, which prevents the temperature from reaching excessive values (or I hope so, having not made any serious measure; in any case, it will always be better than the bulb bearing directly on the plastic body).
The heat sink is a section of 5 mm × 4 mm diam salvage aluminium tube. A 4 × 3 mm tube would have been better. Two 1.5 mm holes drilled into the middle let the “Luciol” type lamp wires go out. It is of course necessary to isolate these wires and hold them with a drop of glue. The 3 mm diam red LED is located behind the lamp.
An additional advantage of this device is that it avoids light leakage on the side (but not at the back, where the LED must be filled). When the red LED is lit, its light must pass through the incandescent lamp, resulting in large losses, which require the use of a high-brightness LED. The actual colour of the LED case is not red, but transparent.