I recently purchased a 99 Tahoe K1500 with 109,000 on it. No major issues presented themselves on the test drive, but over the following week after I bought it, I started noticing several small yet annoying issues that I would much rather fix myself than be screwed by the dealer over.

First up, the lights: The dome light and courtesy lights on the rear doors have a tendancy to flicker occasionally, and some times don't come on at all. If I hit the headliner with my fist it tends to fix the problem temporarily.

Also, the third rear tail light (on top over the rear doors) doesn't work at all. I'm wondering how often these go out, so I know if I should purchase a replacement, or if it's a loose wire somewhere, but I don't know where to check.

Lastly, the rear AC is also not working at all. It doesn't matter what setting I put the knobs on, or if it's hot or cold, I don't get so much as a puff of air coming from the rear vents. This is not really an emergency at the moment, since winter is coming up, but I'd like to get it fixed if it's not prohibitively expensive, and I'm open to suggestions on the cause.

Wishful thinking led to me purchasing a fuse assortment kit that came with a free tester, and I set to work with it this afternoon.

I ran the fuse tester over all of the minis next to the door and under the hood, and the one for REAR HVAC tested bad. I replaced it, hoping that would fix the AC problem, but I still get nothing out of the rear vents at any setting.

Well, I decided to try and narrow down my rear AC problem to see if it was a short somewhere, or if the blower had died on me, so I stuck a 15A fuse into the 10A socket, and prayed that nothing would catch fire.

The rear AC started right up with the larger fuse, but I hastily shut it off again when the acrid aroma of wires getting a bit too hot hit my nostrils.

That narrowed it down, at least, to a short in the system, so I started looking for one. After not having any success with the easily accessable locations, I decided to try another 10A fuse again for the hell of it. Apparently melting wires can fix shorts, because now the 10A fuse doesn't blow, the rear AC works, and nothing seems to be catching on fire.