Is this the fuse you pulled or a different fuse? I looked at info for automatic hvac on your vehicle. The fuse in the diagram shows to be a dedicated circuit, no splices on the wire circuit, goes to havc control module.
It might be possible to use inline fuse off positive battery post. That way you could bypass the fuse block and the wiring circuit both, up to a point. You would need to leave pig-tail wire at the hvac control module to splice new wire. At the fuse block, just leave the fuse unplugged. The autostore sells inline fuse socket. You may not want to get into this, in this manner? Just a thought. Of course if the problem is the hvac control module itself or wire connector at the module, it won't work. I'm just thinking out loud.
It sound like two or three separate problems, but it's hard to tell. The seat belt warning could be a faulty switch which senses a passenger in the seat, while the trunk lid opening could be a battery problem in the key fob. However, if the door locks still work with the same key fob, the problem is more likely with the lock on the trunk. Not starting after stopping could be a battery problem.
From Info I have looked at I believe under hood micro switch relay 35 is for low beam and 34 is for high beam. It also looks like you have a different fuse for each light. The relay are for both low beam or both high beams. each headlight has its own fuse. I believe #4 fuse under hood is for passenger side low beam. fuses 1-4 under hood are for the four headlights as I understand the info I have seen.
bad battery and if i don't drive the car couple of days then it goes dead ??? It's not the battery , you have a parasitic draw on the electrical system , that is what is draining the battery . Could be the instrument cluster .Watch this video .
What's giving out 13 volts or when ? With the engine running hooking a volt meter to the battery the voltage should be 13 - 14 volts , depending on the load on the electrical system. Chevrolet Truck Battery Dies Overnight Part
Does the vehicle have column or floor mounted gear selector ? Both have a safety feature Electronic Park Lock (EPL)/Ignition Lock Cylinder Control Actuator:
Electronic Park Lock (EPL)/Ignition Lock Cylinder Control Actuator: If the vehicle is equipped with automatic transmission and a floor mounted console gear shift, it has an ignition lock cylinder control actuator system in the steering column. The ignition lock cylinder control actuator purpose is to prevent the ignition key from being turned to the OFF position when the transmission is in any position other than PARK and the vehicle may still be moving. The column ignition lock system consists of an ignition lock cylinder control actuator, and a park position switch that is located in the automatic transmission shift lock control switch. The ignition lock cylinder control actuator contains a pin that is spring loaded to mechanically prevent the ignition key cylinder from being turned to the lock position when the vehicle transmission is not in the PARK position. If vehicle power is lost, and/or the transmission is not in the PARK position the operator will not be able to turn the ignition key to the lock position and will not be able to remove the ignition key from the column.
Linear Shift Assembly: If the vehicle is equipped with a column mounted gear shift, it has a linear shift assembly on the steering column. The linear shift assembly has a cable that runs from the linear shift assembly to the ignition lock cylinder case. The purpose of this cable is to prevent the ignition key from being turned to the OFF position when the transmission is in gear and the vehicle may still be moving. The linear shift assembly cable contains a pin that is spring loaded to mechanically prevent the ignition key cylinder from being turned to the lock position when the vehicle transmission is not in the PARK position. If vehicle power is lost, and/or the transmission is not in the PARK position the operator will not be able to turn the ignition key to the lock position and will not be able to remove the ignition key from the column.
I strongly recommend you take it back to the dealer and ask for help. If it is something they damaged, and you have another shop repair it, the dealer is then off the hook for responsibility. The problem could be a blend door under the dash, or the heater core may not be getting proper coolant flow.