Not, easy!
The Bulb comes out from the inside of the Trunk
So, you need to remove the Truck lid inside panel (See Video), reach up behind where the light attaches on the trunk lid, twist the Bulb socket out a 1/4 turn same direction ya unscrew a Jar lid and the Bulb pulls straight out (do not turn the bulb in the socket). Installation is reverse of what I just wrote.
See you tube video;
https://www.youtube.com/watch?v=R7vdo_YsARA
Under the hood of your car should be 2 ports., traditionally these are on aluminum pipes or lines.
It would really be nice if they had two different colored plastic caps on them. Some do.
One may be black, one blue.
Anyway, these two ports are for the hoses of your testing gauge, and for the hoses of the refrigerant.
One hose is high pressure, one is low pressure.
If you wish to do it yourself, you can buy a gauge with hoses at a car parts store, and you will get instructions on how to use it and to charge the A/C with refrigerant, R-134.
God bless your efforts.
during long vacations, it is prefered to disconnect the battery ,to keep the charge ,just disconnect terminals starting by (-)ve ,this advice from batteries manufacturers.
The gas tank is pressurized to about 7 PSI and after that the pressure relief in the gas cap lets go so the condition you describe may be normal or you need a new gas cap.. So you may just be hearing the fuel pump run and it is defective if it is that noisy.