Due the constant bending of the wire harness buddle to the rear hatch when it opened and closed in many cases the wires fail from metal fatigue. What you need to do to get the rear open is remove the trim panel from the inside and manually trip the latch and then perform wiring diagnostics to the various powered components of the rear hatch to locate the broken wire(s).
Battery Disconnect or Replacement Problems
Listen under the hood in engine compartment , see if maybe your mistaken . Disconnecting the battery could cause Electronic throttle control to cycle the throttle plate , DC electric motor on the throttle body . Without hearing for myself ,that's the best i can come up with . Looking at factory service info. ,wiring harnesses , relay's , control modules . I don't see anything behind the instrument panel that could cause a buzzing
Well, the noise could be produce by different things, if its only when backing up then it could be in the transmission depending where the noise is coming from. Do you hear it at the very far end or at the middle of the car? The axle could need a littler grease, also the differential might need to be checked. The differential has few gears in it that could need grease as well.
Have you had the vehicle checked for DTC'S - diagnostic trouble code's ?PCM & instrument cluster ! The chaging system on your vehicle is computer controlled . The PCM send's a message to the instrument cluster over the class 2 serial data network to turn on the light when it see's a charging system problem . As far as it only happening when wet ,water is probably getting into a wiring connection an causing a voltage drop the PCM is seeing as a fault . Check for code's ,not at auto zone . their tool can't read I/C code's . An your not going find any pattern failures for this. The fix ,taking to a qualified repair shop that know's how the system work's . ECM Controlled Charging Diagnosis Alternator Testing GM
You can try pulling the radio fuse for about 3 min. replace fuse and immediately try to eject cd. It might come out. You can try the old butterknife double faced tape trick.. It might work. Take a thin butter knife. Put a piece of double faced tape on the blade. slide (dont Jamb) the blade in the cd slot and slightly press down on blade. You might be able to pick up the cd enough to lift it out the slot. Worth a try. If not you will have to take it to be removed and serviced.
Fuse 3 and fuse 19 in the rear fuse panel power the liftgate module. Check these first and get back to us.
cannot figure out your radio issue. Which radio do you have--premium or standard? Does it have steering wheel controls?
Once the tire is off, you'll need a caliper compressor. I use a large C-clamp to push the piston back to make room for the thicker new pads. I believe the caliper bolts are 15mm. So just 2 tools, a compressor and wrench/socket/rachet, whatever you have.