Heater and A/C Dash Controls Not Working

I have in the past..had to wiggle or remove and reinstall the 12 volt connections on the relays that have blade connections..not the screw on..they seem to be good.

second...looking under the hood ..look at your vacuum lines...wiggle them..engine heat will make the lines brittle and will not seal properly...if so..snip off a a short piece and go to auto parts store and pick up and few feet and replace one at a time..

I hope that helps..

I had a problem like yours where the dash heater/Air conditioner would work at times and then they would not. I brought it up to a friend of mine who is a mechanic and he said to check the ground wires. So on my diesel pusher all the fuses and ground wires are located in one compartment which makes it easy, so I started pulling on every white wire I could grab. Then I pulled on a wire that looked good on its connection, but as soon as I pulled on it, it slipped right out of the connector. I took the eye connector off and replaced it with a new one, and everything worked.

So you probably have a lose connection some where. If it started working while you were checking the battery compartment, it must be in there.

Kind of an interesting added element to this that I wasn't yet aware of at the time yesterday when I made my original post. I had also noted after my ride that I needed to close my LR slide a bit because it had moved just slightly out during the drive (about an inch). When I hit the main control panel switch to close the slide, nothing happened. None of the slide switches had power. The rest of the panel was fine. So that then became 1st priority because I was concerned for rain entering the slide area.

Well, I went back out to the MH this morning to check the fuse / breaker area under the steps. I didn't change-out any fuses, but I did remove and reinsert some, plus I also physically disconnected the battery when I was disturbing all the fuses and reconnected it after. And surprise, the slide switches had come back to life. And so did the heater / air conditioning controls! So there must have been a bad connection somewhere or maybe a little corrosion interrupting the circuit. Sure wish I knew what I actually did! But all's well that ends well. I'll have to pay more attention to cleanliness in that area in the future because the under-step battery / fuse area is very exposed to the elements, especially when driving.

The only thing I'm a little confused about now is how the slide switches and dash heater and a/c switches seem to be connected. If anyone can educate me, I'd appreciate it. Thanks.

What I neglected to mention in my original post is that everything else on the dash is working.. Toggle switches, radio, back-up monitor, jack panel, instruments. I really can't figure out any other fuse on the fuse panel to pull, and there isn't anything that makes sense (to me anyway) on the power distribution box to pull.

theres two fuse blocks ,one under the hood other inside the cab. sure sounds like a fuse.