This is one of those times I'm glad my car can't talk, let alone laugh when a big, complicated problem boils down to something stupidly simple.
The X-11 has earned some laughing rights. Maybe she's just being nice to me because I'm kinda slow, like the time I ran out of gas just a few yards past a gas station...and coasted the damn car a quarter-mile downhill trying to get it started.
Or how about the time I tried to start her up, got nowhere, did some testing and decided that the fuel pump was bad. When I tried to replace the pump, I ended up breaking several bolts in the exhaust system, which is inconveniently in the way of the pump. Ended up having to replace every bolt in the engine end of the exhaust. Got the new pump in, got the exhaust system bolted in...and still had the same problem.
Turns out it was a couple of bad fuel hoses. A couple of bucks' worth, compared to 6 weeks' work and too much money.
Hah. Hah. Hah. Goddammit.
Now, I'm slowly putting things back together after trying to find an electrical fault. For all the circuits under the dash, there's a single common ground, a black wire with a ring terminal that's bolted to body metal (One Ring Terminal to Rule Them All!). I've got the dash in the back of the car, car guts all over the floorboards and back seat, I've gone over every wire and connector, pored over wiring diagrams, sat in the driver's seat and stared at the mess I've made, looking for that damn ground, and all this time it's been right there, dangling from the wiring harness.
Some previous owner screwed around under the dash and ended up bolting the ground terminal in the wrong place: a metal bracket that doesn't touch any other metal in the car. Might as well have left the battery disconnected.
All this time, the only ground for everything under the dash has been a skinny wire and crappy terminal from an aftermarket power radio antenna kit. When I pulled the old radio to try running wire to a newer one, the tenuous connection was broken--and everything either stopped working or freaked out. The air conditioning fuse self-destructed (must have been an impressive burnout).
All this because one wire got put in the wrong place years before I even had the car.