There is nothing crappy about the wiring diagram at all, I would say on the contrary, it is very clear and depicts how the thing is wired, which is the point of it in the first place...

How to test the ballast for an internal short came to my mind:
It is based on quality factor (aka losses) measurement, but allowing you to use just basic instruments you likely have.
First measure the DC resistance of the coil. That would determine what losses are to be expected as "normal".

Then connect the ballast in series with an incandescent lamp (disconnect the ignitor from the ballast and socket, connect the socket to the ballast directly or via an Ameter when measuring the current, put the incandescent into the socket).
Measure:
- The circuit current
- The mains voltage
- The voltage across the incandescent
- The voltage across the ballast coil.
All three voltages must be measured as close in time as possible and with the same meter on the same range, so they depict as accurately as possible the ratios at the same time.
Try to pose the results here, then we (myself or RRK) may do the math, I guess that would be too much for you if you still did not go through any electrical course yet...

Now the theory behind:
Now the 2'nd Kirchoff law says the sum of the lamp and ballast voltages must equal the mains voltage. Because we are on an AC circuit, that sum must be a vector one, taking into account the phase relations. But the meter only shows the absolute values, the sum of just those won't match.
But still we may calculate the phase relations (vs the circuit current) out of them. Plus we know the incandescen is a resistor, so we know its phase shift is zero.
Then calculate the phase shift in the ballast itself, with the current reading its exact impedance, subtract the anticipated lossesfrom the wire resistance and then look at what losses remain.
If the remaining losses is something smaller than the wire resistance, the ballast is very likely good.
But if the calculated remaining losses are way higher, there is very likely an internal short circuit within the ballast, as a shorted turn forms in fact a secondary winding (that turn) with the turn's wire resistance as its "load".

Well, nothing crappy with this schematic. Connections look legit. Now you can lift ballast cold lead and lamp hot lead connection (black wires) from the ignitor board, disabling the ignitor, and probe the circuit safely. I would just use ~100W incandescent with two wires to probe, as multimeters can be sometimes misleading having too high input impedance and picking capacitive interference instead of a true voltage.

First, connect the incandescent lamp across the lampholder. It should light up at about half brightness. If it does, okay, ballast and photocontrol is good. If it does not at all - there is a circuit break somewhere. If it lights up at full - the ballast is shorted.

Next, I would try the trick with an incandescent and a fluorescent starter as a makeshift ignitor across the sodium lamp.

There may be tough cases as the choke partially shorted, hard to diagnose without some specialized tools. You can try to connect the choke right across 120V line directly and measure short circuit current. Should be around 2-2.5A AC I assume. Be careful as if the choke is really shorted, you can expect some fireworks ) Use some current-liminting in the circuit, at least 10A breaker, better something like 1KW heater or large lightbulb. Better use something short circuit resistant as a current clamp, as you can blow multimeter 10A input that way.

The ReStores around me seem to sell whatever they can get their hands on. Last time I went, I got an ElectroPak 35w HPS wallpack of 1980s vintage. Every time I've gone, they seem to have something interesting, and they don't have a problem with selling fluorescent or HID lamps/fixtures. However, they don't have particularly high prices, and the items are usually on sale.

The two Goodwills near my house don't seem to care about mercury content in the products they sell. Both of them use traditional means to light the stores - MH in the parking lot, F32T8 or PL fluorescent indoors. Only one LED in sight - a small strip lighting a convenience cabinet. You can usually tell which thrift stores care about mercury content by the lighting they use - if it's converted to LED, it's unlikely you will find anything. This does not always hold true, as the Value Village down the way doesn't seem to care either, and it's converted fully to LED (except in the parking lot, where it's MH.)

I've found that thrift stores that are run by churches tend to have very good prices. There's a place called PACS Thrift in East Portland that sells things at bargain-basement prices. They usually have some very interesting things in regards to lighting. It was there that I found a 275W SBMV reflector lamp. Now THAT was quite a find!

Here you go, RRK and Medved. Please excuse the crappy schematic, I have yet to take physics / electronics class. 

Just purchased two more Metal Halide Wallpacks for my garage... which means 8 Metal Halide wallpacks in total.
THAT'S IT... in terms of my garage lighting. I will not be doing anymore lighting installations in that garage after this.
But... when all is done, this will be my most successful lighting set up thus far. And 8 Metal Halides firing up... that...
will be epic to see.

Just bought a new strut for my sport car to fix the strut issue I've been facing for the last 3 months. (Two new rear struts) Added to that, I've
got incoming money on the way for an additional car, (this next car will be a non turboed automatic... for my daily usage.) AND, just purchased my
final two Metal Halide wallpacks for the garage. (will be 8 identical MH wallpacks in total)
... sweet. 

Maybe if you may also take more detailed photos of the ignitor board (the topside showing the components, also the bottom side so the connection could be traced), it seems to be something else than the usual semiparallel type...

I had 2 jeeps that had the 5 speed trannies.  An 89 Cherokee, and an 89 Wrangler.  They were fun but that was when I was younger. Now a days I appreciate the auto trannies.  Now.. If I had a sports car I might enjoy a manual but we'll see.

I'm with you on that...still like stick shifts, even though I don't own any currently. (Getting older stinks. )
(Used to make fun of "granny tranny" cars back in the day...Oldsmobile and Buick especially. )

Okay, will do. Thanks for bumping me in the right direction.

May be the wiring is messed up. Please do us a favor, draw a schematic in a normal way. It is super simple here, but we can't decide it from single photo shot from a single angle, where black wires are going into darkness...