2004 Jeep Grand Cherokee Laredo 4x4 V8 Won't start

I'm wondering if all of these items are related electrically, because my 2004 Jeep Grand Cherokee V8

1) won't start,Gas gage says empty but tank is full.
2) AC clutch isn't turning so AC doesn't work.
3) Windows won't go down even after checking all wires in door jams they're good, and replacing master control on driver door.

I've checked all fuses they're fine, I even replaced the relays. Windows stop working so I went through the process of all the checks. Tried to use the air conditioner because windows wouldn't go down, that's when I noticed the AC didn't work.
Two weeks later while still trying to fix the other 2 problems now it won't start, gas gauge indicating empty even though the tank is full.
Anyone know if they are related electrically? Or what to do?

 

Start with the basics like strong or freshly charged battery, check ALL connections on the battery and ground cables (more than one) for corrosion or breaks. Gas gauge probably won’t read if there is lack of power. AC may be low on refrigerant thus clutch won’t engage. Focus on the start problem first. Old fuel? Any rodent damage to wiring harness?

 

Check the boot between cab and drivers door. Common for 10 ga ground wire to break and cause most of the problems you mentioned.

 

AC had plenty of refrigerant, In fact it had too much had to drain some. Fuel is new just filled the tank. Checked the wiring for the windows replaced a couple that were broken. Battery is new, but I'll check how strong it is again. I been driving it fine ever since I purchased it purchased it in February, then all of a sudden the last couple weeks this stuff happened.