Several hours of testing the left panel functions have produced good results. One switch was mis-wired (easily fixed) and there is a short somewhere in the wire between the A/P switch and the A/P harness D-sub connector. I'll open the D-sub hood to track it down, which shouldn't be too hard. I haven't yet tested the low voltage and overvoltage protection circuitry, but on all other circuits, DC power is showing up when and where it's supposed to show up, including the oil pressure switch, fuel tank gauges, elevator trim actuator, etc. The lighting circuits, dimmers, and LED indicators work, including the LED indicator wires going to the center panel. Load stress testing will be done after avionics and other gear are installed.

There were a couple of false starts when something didn't seem to work as designed at first -- resulting in considerable head scratching -- before I realized I needed not one, but two or even three fuses in place to allow that function to work as it should. I burned several fuses, but only because it's not easy for my clumsy fingers to place the VOM probes in some of the tight spots -- like the back of the radio stack -- without shorting out to nearby metal.  No problem, that's why I was using small fuses! It was great to be able to print out the Fuse Assignments page of the electrical spreadsheet, as it was an excellent guide and logging tool for these tasks.

There were surprises, mostly of the good kind. The first circuit I tested on the MAIN BUS was the START button -- just because it's at the top of a column of fuses. The starter contactor clunked ON just fine, but I was so focused on the voltmeter connected to the output that I was momentarily very surprised to see the associated red LED flashing away -- just like it's supposed to! What a fine sight. (That LED indicates the starter contactor is activated. If it continues to flash after the START button is released, it would indicate a stuck or otherwise faulty contactor, or toggle switch.) This momentary astonishment upon seeing an LED suddenly fire up when it was supposed to happened several times. Great fun! 

The bottom line is that after planning this over a period of years, followed by many months of building, not to mention tweaking and re-building, it is incredibly satisfying to find almost everything working just as it should on the first go.