Microwave and fireplace does not turn on

You will need to check the 12VDC fuses first. Each slide should have it's own fuse for motor protection. If they are all good, are you able to access the wiring going to the motor? If so, have another person push the switch while you check for voltage going into the motor. If you have voltage, the motor may be shot.
Hopefully, you have the hand cranks that are supplied with the camper, you will need to find the spot where you access the motor to manually close the slide.

Some programmable thermostats may have a battery backup under the cover. Check your owners manual to see if this applies or remove the cover too find out for yourself. If the programming is dependent upon the battery it your camper for it's memory, check to make sure the battery disconnect in closed/on to keep the memory settings stored. Worst case scenario, you might want to consider buying a new thermostat that does have an internal battery backup, but they are not cheap.

Check water heater blender valves to see if they are all the way open and not in bypass

There isn't much you can do but fill up your tanks with clean water and drain it. Their is probably something that was in your tank that is hung up on the sensor and it is giving you a false reading. I live and work at a campground and I see this everyday. The sensors don't work half the time as you will find out the more you use you camper rv.

possibly gear arm is bent. slide outs are not made to be sat and lived in. you should be able manually slide it in. try to lift slide out by the arm with a hydraulic jack. place jack on ground use a 2x4 or 4x4 between jack and gear arm and lift gently. the teeth on arm could be stripped also. just ease into it..

I have used Curt brand controllers on a GM Silverado and a GM Express van. On the Silverado I had it installed parts+labor for $150. Hardly worth messing with it myself.

I have had to replace one on the road I accidentally broke. I found the replacement at a U-Haul rental place. Changed it out myself at the campground. They are readily available, function great, and reasonably priced. Connecting to the wiring is probably different from model and make to another.

120-
VOLT
AC
SYSTEM
The following electrical components (if so equipped) will only operate when your
RV is connected to shore power: 120 to
12-volt power converter, air conditioner,
120-volt refrigerator, microwave oven, television(s), fireplace and appliances
plugged into convenience receptacles.

SECTION 6 - ELECTRICAL SYSTEM JAYCO TOWABLE
6-2
120-
VOLT
CIRCUIT
BREAKERS
The 120-volt AC circuit breakers located in
side the main load center protect all
120-volt wiring and components in the RV fr
om circuit overloads and short circuits.
Should a circuit overload or short circui
t occur the circuit breaker protecting the
affected circuit will "trip" preventing the flow of electricity through that circuit.
If a circuit breaker trips, shut "off"
the appliance on that circuit (i.e., power
converter etc.) and allow the circuit breaker to cool down for a brief period of time.
After the cooling down period, reset the circuit breaker by moving its lever "off" and
then back to the "on" position. If the circuit breaker re-trips or frequently trips,
contact your dealer to have the electrical problem diagnosed and repaired.
A circuit breaker identification label is permanently attached to the inside surface
of the 120-volt load center.
Maintenance and Replacement
At the beginning of camping season, inspect the circuit breakers and replace as
needed. Test by turning each circuit breaker "off" and back "on". Circuit breakers
are wearable parts and must be replaced
as needed, as part of your RV
maintenance. If you have any questions, consult your dealer.
Please contact your dealer for repair assistance when replacing circuit breakers.
CONVERTER
The power converter converts 120-volt AC power to useable 12-volt DC power
when the shore power cord is connected to an external power source.
The converter has a built-in protective thermal breaker that will shut it down should
overheating occur. Overheating can be
caused by operating the converter above
its maximum power output for an extended period of time, or by an obstruction to
its ventilation air flow. To reduce converter heat build keep unnecessary 12-volt
lights and motors turned "off"
.
Keep the converter cooling fins and fan clear of
obstructions.
Inspection and maintenance
If the 12-volt power converter is not working (auxiliary battery not being charged)
check the reverse polarity fuse(s) in the converter fuse panel.
There are no
customer serviceable parts inside the converter case and the
manufacturer's warranty will be void if
the case has been removed
. If you
have further concerns contact your dealer.

It is the switch to turn on and light the gas FP

Possible bad connection...weak battery...
Let me know what you discover.

fuses