Difference between revisions of "Switchcraft"

Revision as of 21:18, 25 May 2008

Switch source

The electrical switches used in the Elan come from Vauxhall (UK GM) cars of the same era. Carltons, Astras and others can provide useful switches for the front panel to the window and door mirror switches.

Front panel switches

One difference is that the Elan switches have orangey-red markings whereas the GM switches are white. One way of making a white logo match the rest of the switches is to use a red CD pen as in the heated rear windscreen switch on the left of this picture:

If the backlight illumination lamp or LED fail (or you want to change the colour of the LED) you will have to remove the switch as they are both soldered in. The lamp cover at the top of the switch can conveniently be pulled off providing purchase for a pair of small pliers at the position marked with the red arrow in the left hand picture. There is a retaining latch at the bottom of the switch and the easiest way of releasing this is to push a key or similar almost vertically up through the cutout in the bottom of the switch. This is shown side on in the right hand picture below for clarity: the key enters via the cutout (red arrow) and pushes up the retaining cantilever (blue arrow) thereby releasing the retaining latch (green arrow). The switch should pull out but if it does not, the switch panel may have to be released and the switch pushed from behind.

With the switch removed, the first job is to open it up. It is held together by four retaining latches marked by red arrows in the left hand picture. An easy method is to insert two thin bladed knives at the positions shown by the green arrows to open up the switch body then to insert a third knife or small screwdriver at the position shown by the blue arrow and to use the latter as a lever to get the switch apart. The three knives are shown in action in the right hand picture:

The body of the switch should pop apart and open up to reveal the lamp and LED. In this rear foglight switch, the cathode (marked by a flat on the LED body) is connected to the centre contact (pin 2) and the anode to the right hand centre contact (pin 4).

NOTE: this switch has a Lotus part marking B100M6004F and does not have a 2kohm resistor {red-black-black-brown-brown} between the anode and pin 4. These resistors are shown in the Rear foglight circuit diagram and are present in the equivalent GM switches. This is slightly worrying as there would not appear to be a suitable place for including the resistor in the wiring harness. If you use a switch that has an integral resistor, it may mean that the LED does not illuminate very well but will not affect operation or safety.

In the middle picture, the lamp has been changed. Now, the original lamps are about 10mm x 4mm diameter with long pigtails. As I have not been able to find a suitable source, I have used a 1.2W Type 286 capless lamp; these are 17mm x 5mm diameter so some modification to the switch body is necessary or the lamp will sit too proud - as shown by the blue arrow in the middle picture.