I've been out working on the car tonight and I noticed something odd. With the headlights off and whether the car is started or not, when I depress the brake pedal the interior dash lights illuminate as do the front parking lights. When I take the foot off the brake pedal they turn off.

I'm not sure if this is a new phenomenon or something that has happened on my watch. I recently washed the engine but this seems like an odd result. I also have the heater control panel and all of the connected items removed while I replace it. I also removed the clock and tried to clean it (and I changed it's bulb). None of those things are particularly logical causes of this. All fuses are good....

Any ideas or ways to troubleshoot?

Check your Hazard Switch.

That connects all those circuits.

E

And another thought is that if the non-brake lights that come on do so dimly, you need a better ground.

The parking lights seem to come on quite brightly. I do have one headlight that is far dimmer than the other. I also just repaired the 'dome light' - cleaned it out, changed the bulb, and it worked perfectly. Now it doesnt work at all. Is it possible that during engine cleaning I knocked loose some electrical connection in the engine compartment? How in the world do you troubleshoot something like that?

You need a wiring diagram so you can trace the circuits.

.......and a multi-meter.

nothing in the engine compartment is going to affect the dome light (except disconnecting the battery!) check your fuses with a multi-meter (don't just look at them, TEST them)

Are there any threads out there on multimeter 101 or any tips you can give. Once again - all of this is new to me but I am dying to learn....

The file attached is a manual for a specific brand/model of multi-meter. It has a lot of information on general electrical testing within it. Your meter may not function exactly like this one, but the general testing information is IMO quite helpful.

Generic Electrical Testing Info.pdf