I finally fixed the problem on my 1990 740T. I was looking at rewiring the entire headlight, brakelight, and running light setup because I could not find any of the headlight relays and the running lights are turned on by the headlights, probably at the relay.

I checked fuses, wiring, the switch, and even the socket. I disconnected the bulb socket board and still blew a fuse. (I blew 35+ fuses in the course of two years). I disconnected the front and rear sockets and tested for resistance similarity across the two boards and each bulb socket.

I had finally given up and was starting to buy my new equipment piece by piece so that I could be sure I couldn't have a problem like an old circuitboard interfere with my new wiring. While wiring up my temporary fix to no running lights on the right side, I found that two similar looking brake-wires were spliced together (my mechanic worked on this thing at some point while my dad owned the car) but one was not providing voltage with the brakes. I capped this wire and another odd grey wire, and ran a single wire from one fog light to the other. I spliced the wire providing juice to my brake lights into the brake light socket and left the car alone. I didn't try another fuse after changing this.

I have been very busy starting another semester of college (I'm headed for an engineering degree), and just had to do something with my free time tuesday. I replaced a rear seatbelt and installed the bulb sockets I ordered. I went up to turn on the brake light and parking lights and noticed my "bulb out" light was off... "Oh NO way" thought I. Once I installed the fuse, the only thing I had left to do was replace all the internal blue/green lighting behind the dash, etc. I haven't done this yet because supposedly the bulbs are 6$ per and I need about 5, and I'm not sure they are supposed to be blue (in appearance). I'm interested in all-red lighting conversion of the internal lights but concerned about how the red needles will appear on the instruments. Red is not my favorite color, but is much easier on the eyes.

If anyone had pics of a red-light conversion, let me know. After all the work I put into the problem and the strangeness of my problem, I'm still aggravated that I didn't really find the problem. It was accomplished because I was thorough, but that isn't really something that I deduced myself.
I'm going to simply be happy it's working.

Thanks to the few who replied,
-Will740T