I have a 2003 H2 and lateley while driving it when I get home I have smoke coming from my right rear wheel area. It smells kinda of metallic and plastic burning. I looked and looked the only thing hot is the exaust and the hub. I took it to the dealer and they couldnt find anything wrong but it just did it again tonite and just from driving 20 miles. I hear a popping fizzing sound from the area too. Anyone have any ideas to whats going on?

 

The burning smell your describing sounds almost like brakes (same smell you get when you burn a clutch). I would pull the wheel and inspect your caliper/rotor, Im guessing you have something hanging up. Pull the caliper and check the pads for uneven wear as this will be a tell tale sign something is hanging up. Then make sure that the caliper slides move freely with little to no resistance..... if they do not move freely pull them apart and grease the slides/shafts with a good synthetic caliper/brake grease. If the pads display any signs of uneven wear you should replace them as well.

If the regular brakes are showing no sign of hanging up then pull the rotor and inspect the E-Brake shoes for signs they are dragging, there is an adjustment wheel between the two shoes. If these are dragging make sure that your e-brake pedal is releasing properly with no slack.

 

Recall. Check your vehicle for manufacturers recall. Hummer are known for A/C connection failure. Get it fixed. Where there's smoke fire will Follow

 

Roof drains are back there, it's possible that water is draining down and dripping on the brakes, making it pop or sizzle when the brakes get hot. I would think the dealer could find a dragging brake or a leaking brake cylinder.

 

I had an issue on the rear brakes where the caliper wasnt releasing the inboard brake pad all the way and it was dragging. Ended up redoing all the brakes and replacing the rotors because the back side was dug all out. Maybe it could be what you are seeing.