[carcrazysincebirth]

I have a 2004 GMC Sierra crew cab with a 5.3. Last week I noticed that the right tail light was out. I picked up a bulb, but the old bulb ended up being fine. I figured it might be moisture, so I sprayed some penetrating fluid into the socket, but still no light. After a couple of nights, I checked to see if the right tail light was working yet, but was surprised to see that neither tail light was working. Besides that, the brake lights are not working either, except for the 3rd brake light mounted over the rear window! Since then, I checked almost every fuse inside the driver's door and under the hood. No burnt fuses! I looked to see if anything was jammed into the factory trailer hitch plug, but it looks clean. I looked up at the light module under the rear bumper to see if any wires were hanging, but nothing stood out. Can somebody help before I get over-charged again at the local dealership??
Thanks