912is Wiring
Have reached the point where I have hooked up the 912is as it is shown in the Kitfox manual which electrically corresponds with the Rotax Installation Manual. The bad news is that it doesn't appear to be working as I think it should. I am using a G3X and have wired the FADEC CANBUS as called out in the Garmin instructions. When I turn on the battery and then the Lane A and B switches, the A and B LEDs are non-responsive as in no flicker or anything. I saw an earlier post by Eric Page talking about the 1.5K resistor being the wrong size (1.5ohms versus 1.5K) which loaded down his lights. Checked my resistors and they are correct; 1K inline and 1.5K parallel to the LED. I looked at my G3X and the Rotax FADEC is grayed out (doesn't see it) so am thinking that my ECU is out. Saw a post somewhere talking about having a similar issue and when either the Start Power or the Back Up Power switch was selected, it all woke up (but unfortunately didn't have a description of what the issue was that I can remember). So I tried that and with the exception of the Lane A and B lights still not working as expected, the system appears to connect with the G3X (i.e. The FADEC is no longer grayed out and when selected, shows that is indeed talking to the engine with all the pertinent information and can see the proper engine instruments show up. Also interesting is that when I switch the Lane A and B switches on and off, the correct engine instruments controlled by those two lanes go on and off as well). The minute I put the switch back into the center position, the FADEC disconnects and grays out again. There is the three pin power switch on the fuse box and I have checked that. Pins 1 and 2 power as advertised when the Start Power/Back Up switch is switched. Pin 3 has 12VDC on it at all times. So the bottom line is that the system appears to be acting like it's losing power or ground. I have checked the switching ground side of the Start Power/Back Up switch and it too is working as advertised. The Lane A and B sides are indeed isolated ground wise from each other till to flip the Start Power/Back Up switch which since that causes the FADEC to work, makes me think there is a ground issue. The B side is grounded to the airframe/engine.
