A new instrument

I can't say I was particularly thrilled about cutting a new hole for an instrument in a panel I'd already painted -- there's really no way to avoid some scuffing in an operation like that -- but on the other hand, I've always really liked the Electronics International fuel level gauge, which has a descending series of LED lights to indicate fuel level in each tank. I've always liked pretty colored lights.

And, as it turned out, the Grand Rapids EIS (engine monitoring system) is better for the fuel flow indicator than the fuel level, so I wanted two data references in the panel to track this sort-of important thing. Plus, the EIS seemed kind of lame in the wiring, requiring a resistor to be connected between the wiring and the fuel level sender in the tank.

So today I punched through a new hole, and installed the EI fuel level sender. That's it just above the red knob (the mixture regulates the fuel and air mixture). Glad I left a little expansion space in my panel design.

I should be able to get it wired up pretty quickly. It's very simple, from what I can tell. Even I can't screw it up.

Next to it is the TruTrak autopilot. I have a wing leveler system but haven't been able to wiring it up fully yet because of some questions I have about how it's tied in to the GPS.

I sent a note to Stein at SteinAir but haven't had a chance to get together with him yet, but maybe you can help in the meantime. Here's the questions:


On the the transponder, there were two wires remaining with no apparent home:
SERIAL OUT 1
SERIAL IN 2

My setup is the Trutrak single-axis and the Dynon D100. The only GPS I have is a Garmin 296 in an Air Gizmo, although I'll probably upgrade to a 496 before I'm flying. Do these two wires have significance with my equipment and if so, where and with whom do they mate?

I'm also looking at the TRUTRAK harness kit with these 6 loose colored wires:

RED WIRE -- Power (I know what to do with that)
BLACK WIRE - Ground (I know what to do with that)
BLUE WIRE - Serial input from GPS (I bought the GPS Garmin cable, I assume this attaches to "Blue: Port one out" or "Violet: Port 2 Out". Is this correct? If so, does it matter which?
YELLOW - Dimmer (I know what do do with that. I think)
GREEN - To Altrak Pin 9. Since I don't have Altrak, I assume I just insulate it and wait for the lottery to do its thing.
WHITE/BLACK - To control wheel switch (from pin 2). I have on idea what this refers to. What control wheel switch?

Meanwhile, I have about three or four instruments with wires to a dimmer. Anyone want to guide me on how I would wire several instruments to one dimmer switch?