Dash board goes dead

Question edited for clarity and fix typos
Question moved to RVs.

Propane is a very specialised fuel to run an engine on, so my answer is somewhat of a guess based on logic. You are running out of gas, literally and no pun intended. The gas is in a tank with a regulator which supplies gas to a manifold and the gas pedal tells the throttle body to let in a certain amount of propane and air based on the amount the gas pedal is down. Something in those items is not doing its job. This link seems to explain the system quite well.

https://afdc.energy.gov/vehicles/how-do-propane-cars-work

This link is your engine and forces pages that mention propane as a fuel.

https://www.google.com/search?q=chevrolet+5.7++%22propane%22+bogging+down&

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Experiencing difficulties getting the vehicle out of park, starting the engine, and having all gears appear to be in reverse can be indicative of a few potential issues. Here are some common causes and steps you can take to diagnose and possibly resolve the problem:

1. Brake Light Switch: The most common cause of not being able to shift out of park is a faulty brake light switch. This switch is connected to the brake pedal and needs to be engaged to release the shift lock mechanism. If the brake light switch is malfunctioning or misaligned, it may prevent you from shifting out of park. Check if your brake lights are working when you press the brake pedal; if they are not, it's likely the brake light switch that needs replacement.
2. Transmission Linkage or Cable Issue: If the gear selector is not accurately engaging the transmission, it may cause the transmission to stay in reverse even if you've shifted to another gear. Inspect the transmission linkage or cable that connects the gear selector to the transmission to ensure it's properly adjusted and not damaged.
3. Transmission Shift Solenoid Problem: Modern vehicles use shift solenoids to control gear shifting in the transmission. A faulty shift solenoid could result in incorrect gear engagement. Have a mechanic perform a diagnostic scan to check for any transmission-related error codes.
4. Low Transmission Fluid Level: Low transmission fluid can lead to improper gear engagement and cause the transmission to stay in reverse. Check the transmission fluid level and condition. If it's low or shows signs of contamination, refill or replace the fluid as needed.
5. Ignition Switch or Neutral Safety Switch Issue: Problems with the ignition switch or the neutral safety switch can affect the starting process and may also impact the transmission's shifting behavior. A professional mechanic can test these components to determine if they are causing the issues.
6. Electrical Issues: Faulty wiring, connectors, or sensors in the transmission or related systems could contribute to the problems you're experiencing. Have an electrical system checkup to identify and address any potential electrical problems.

Due to the complexity of the issue and the potential safety risks associated with transmission problems, it's recommended to have a qualified mechanic inspect and diagnose the vehicle. They can use specialized tools and experience to pinpoint the exact cause of the issues and provide the appropriate repairs or adjustments. Trying to diagnose or fix transmission-related problems without proper knowledge and equipment can lead to further damage and costly repairs.

Thor Motor Coach A.c.e 29.2 RV, class A motor home.
well go to the RV center and buy the books for the drivetrain.
or go to makes web site and ask for the same
what is there can vary Engine , Transmission and HVAC.
what makes you think any 2013 RV or car uses vacuum for HVAC dampers/ most are motor drive.(gear box)
dead blower is. (the front blower in dash up front?)
1: blow fuse.
2: or controls to blower failing,
buy the service manuals, for sure drivetrain and HVAC.

If this is a manual transmission then it sounds like your clutch is worn.

Replace the fan motor.

My first two suggestions are related to the ignition switch and the gauge cluster. I like to try a "wiggle test". Sometimes it is a great way to narrow down a search. Put the key in the ignition and turn the key to the run position (do not start the engine) and wiggle the key and turn or rock the key slightly. You want to see if maybe the ignition switch if faulty. If you notice nothing from this test then it may be fine. Next would be to remove the gauge cluster and inspect the harnesses that plug into the back side of the unit. Over time dust can work itself into connections and cause havoc on circuits or systems. I will say that from your description, it sounds like a soldered joint, loose or over-heated wire is related to this problem. At this time I can not give you a good recommendation. I can tell you that somewhere where, something has worn out. It could be related to wiring, the fuse box, ignition switch, gauge cluster, or ECU. Please write back with more questions or findings. Please be as specific and detailed as you can. I hope to hear from you soon, good luck.

Sounds like there may be a loose ground wire from the instrument cluster to a metal chassis point.

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

should be under the motor home along the frame follow the fuel line

May be the transmission interlock. make sure the shift lever is firmly in park or neutral. or sw may be bad. sw located at tran where linkage is. can short it to see if eng starts.