This instrument panel lighting stuff gets more complicated the deeper I get into it. So far I've got two B&C Specialties solid state dimmers, one for a gooseneck map light/supplemental cockpit light/emergency instrument panel light, and one for two LED flood lights. These solid state dimmer modules vary the output between 4v and 14v (i.e. system voltage).
Microair 760 Com display back-lighting - it works well when connected to the same dimmer module as the LED flood lights, and the back-lighting only draws about 0.03 amps. However there is an LED indicator that illuminates when the radio receives or transmits, and it does not dim. This LED is very bright at night, so it will be a nuisance. I'll probably end up covering it with something at night.
GNS-430 - the display and key back-lighting are extremely customizable. It could be set up to be controlled by the same dimmer module as the LED floodlights. It can be set up to switch its control to a photocell once the dimmer goes to a predetermined low voltage - i.e if you put the dimmer control to its minimum setting in the daytime, the GNS-430 will automatically vary its display intensity to match the ambient light level.
GTX-327 - it is fairly customizable, but the voltage level at which it goes into daytime mode cannot be varied. It won't go into daytime mode until the input voltage drops to about 0.35v. I thought I had a bright idea to use a zener diode to drop the solid state dimmer module voltage down to less than 0.3v. I invested $0.39 in a zener diode today, but my idea didn't work when I tried it tonight. So, I started wiring a small 2.5k ohm rheostat. One end of the rheostat goes to ground, the other end to 14v, and the variable output will go to the GNS-430, GTX-327 and trim indicators. The rheostat will draw a constant 0.0055 amp, even in the daytime, but I'm going to lose any sleep over that.
Ray Allen electric trim indicators - The trim indicator intensity can be controlled, but they are set up quite strangely. They go to a fixed low intensity if the control voltage is present, and go to a high intensity if the control voltage is below about 0.35 volts. The solid state dimmers don't go to a low enough voltage to kick the trim indicators into bright mode, so they will need a rheostat.
Grand Rapids EIS-4000 - it's display back-lighting is not dimmable. It seems to be set at a constant medium level. Time will tell whether it is too bright at night.
Annunciator panel - I'm still struggling with what to do for the four annunciator lights I'm planning. I haven't found anything reasonably priced that looks as professional as I want. I want some sort of light with the legend right on the face. At the moment I'm considering some LED light bars from Stanley Electric. Some other builders have used them and seem to be happy. One other builder thinks they are not bright enough, but I suspect that depends on how much you are willing to overdrive the light bars by running them at more than the rated voltage. LEDs are fairly tolerant of being over-driven, and they won't be ON that often, so I don't need a super long life. I think I will order a couple to play around with. They will get their own Bright/Dim switch.
Other - the Garmin GI-106A CDI (0.3 amp), Van's engine instruments (0.15 amp each) and magnetic compass all have incandescent lighting. They will get their own solid state dimmer.
Two shipments of odds and ends arrived today, so I can re-attack the roll trim wiring, etc.
