Durango 2002 A/C plus ...

Hi, Gurus, I have spent hours searching this group for the answers to my problems, and I'm not sure I'm any nearer the solution.
The A/C in my 2002 Durango is pretty average, and I am at a loss as to why. The air takes ages to cool down, but on really hot days it doesn't get very cool at all. I have tried to find a difference between outside and inside air, such as a blockage in the recirc system, but the flow is the same, and not very good. Sitting in the back (the car has rear seats and A/C), there is very little flow, but more on the left side than the right, and even then it's generally warmer than the front. There is no problem with the gas levels, as they have been checked and re-checked. I live in Dubai, UAE, and being on the edge of the desert, there is a lot of sand and dust blowing about. I am wondering whether there could be any exposed heat-sinking surfaces that could be clogged up with sand, and easily cleared with a bit of well directed air. And also whether there are any issues with the flaps / valves involved in directing the airflow within the system to the right places. On a completely different note, when listening to music at volumes loud enough to be heard, there is a really loud buzzing sound coming from all four main speakers (in the doors) which sounds like the speakers have blown. Now, I can't believe that all four speakers have blown in exactly the same fashion, so I want to take the covers off the inside of the doors and have a look, and give them a good clean. I suspect they also have a good deal of debris in them which is causing this buzzing. So I need to know how to take the trim off - it looks like a couple of screws and a load of clips, but I'm not sure - any pointers?? Thanks in anticipation, Cheers, Ed
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