Factory, 77-on. Showing two different types of bulb arrangement, and damage to a third caused by heat from the bulb (Phil Townsend). Although the position of the bulb indicates that the damage is more likely to have come from the design on the left, and perhaps the middle switch is a redesign to overcome the problem, Phil reports that both types suffered damage, and he fitted LED replacements as here. However the design of the 'bulb' means that it doesn't make proper connection to the spring, as there is a hole in the spring, and instead of a largish blob of solder on the end of a typical incandescent bulb the LEDs centre contact is much smaller which doesn't make contact with the sides of the hole. In Phil's case these switches are illuminated with the parking lights, not to indicates that a switch has been operated. But Mike Carter with a 1980 LE says his only illuminate when they are turned on, not with the parking lights! The factory wiring diagrams clearly show night-time illumination wiring (white/red and black) going to all switches and the heater controls. I can imagine a shutter behind the rocker allowing more light to come out with the rocker down i.e. switched on than up, but I can't imagine being able to see it at all in daylight
To access the bulbs the front of the rocker can apparently be prised out by carefully using a thin blade between the rocker and the housing as indicated by the red circles.
Wanting to resolve problems on his 1980 HRW switch (which for that years reputedly had night-time as well as tell-tale illumination) Albert Ross took these pictures of his switch and wiring:
This is the 1980 switch which has multiple pins on the back and several wires in the harness connector. Three of the wires seem to be white/black, which is the colour for the wire to the rear screen, but why three? There would be two if there was an external tell-tale as prior to 1980 but this should have an internal tell-tale. If that connection couldn't be made inside the switch then I could see a loop on the back, but again that would only be two wires. Green is the 12v supply for the screen, and white/red the 12v supply for the night-time illumination which uses the spades on the side of the switch. There should also be a black earth wire for the night-time illumination (and internal tell-tale), but that's not shown for some reason. I don't have a diagram for a 1980, those for 1997-99 only show two connections to the switch (on the back) for the HRW and two (on the sides) for the night-time illumination.
He happened to have a spare pre-1980 HRW switch which he dismantled:
This shows just two connections on the back (green 12v and white/black to the HRW and external tell-tale), plus the two on the sides and of course only one bulb for the night-time illumination. The rocker has a green lens, presumably that is what the night-time illumination would shine through, which would still be there when it was turned on at night. The fascinating question is, how does the 1980 tell-tale function differ to that!? It can't be that same bulb is also lit when the HRW is turned on in daytime as that would light all the other lights including the parking lights at the corners of the car. Maybe the switch has a secondary function that disconnects the bulb from the white/red and connects it to the white/black. Who knows?
Cut at the copper strips, three elements minimum
Connector block ...
... but heat-shrink is just as effective and less obtrusive
1/8" gap on my roadster ...
... the V8 has beading in this gap, but it can be lifted out of the way.
Almost invisible when driving
Way too bright at a full 12v
Brightness reduced with a resistor. The reflection from the dash panel and tops of the fresh-air vents looks like it might be distracting compared to the illumination of the switches and controls, but in practice it isn't.