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Buellah · 05-17-2021, 09:02 PM

Well, I guess the title says it all. Dash A/C works just fine when the engine is at idle or when I’m not on the gas driving down the road. As soon as I give it a little bit of throttle, the air coming out of the dash vents heats up and eventually gets pretty hot. Let off the throttle, it eventually cools off again.
It’s a new unit and is under warranty, however, it takes a while to get on dealership schedules, if it’s something that the A/C fairies can take care of and I can have consistent dash air, all the better. I’m heading into the wonderful Phoenix summer and the only way to get to somewhere cool is to drive up a mountain...for now , with no dash air.
Thanks for any help offered.

D20 · 05-17-2021, 10:11 PM

The coolant valve is not closing all of the way. When you speed up the engine, the coolant pressure increases and goes by the valve. Common problem, from what I read.

Mine also was working intermittently but it finally is working correctly. I guess I cycled the valve enough from hot to cold to free it up so it would close all of the way. Time will tell if it stays “fixed”.

I would suggest that you start by cycling the valve from all of the way hot to all of the way cold over and over by using the temperature control on the dash. Give it some time in each position to give time for the valve to move all of the way. Additionally you can pinch the coolant hose just before the valve to try to get the valve to seat. Or if you are desperate, you can install a ball valve in the hose just before the coolant valve and just close it for cold air.

I assume you have an Evans Tempcon / ProAir system. Good info here for further troubleshooting. https://www.proairllc.com/design-eng...empcon-guides/

chboone · 05-17-2021, 11:16 PM

If it's not the compressor or the very few components supplied with the chassis from Ford it will be the the MH manufacturer problem because they supply the main components of the dash A/C system.

mack73 · 05-18-2021, 08:15 PM

Check if the AC compressor clutch is disconnecting when you increase the RPM's. Easy to do by just looking at the compressor pulley. When the clutch is engaged the center spins with the outside edge. When it is disconnected the center will be stationary while the outside continues to spin with the engine belt. If the AC is on, the clutch should be engaged and the center is spinning.

The AC system has a high pressure cutoff switch. If the system is overfilled with 'freon' it can over pressurize when you increase RPM and disconnect the clutch meaning no AC = hot air out the vents. When you reduce RPM the compressor is generating less pressure (turning slower) so the high pressure switch allows the clutch to re-engage and cool air is back.

tarjas · 06-16-2021, 09:10 PM

Quote:

Originally Posted by Buellah

Well, I guess the title says it all. Dash A/C works just fine when the engine is at idle or when I’m not on the gas driving down the road. As soon as I give it a little bit of throttle, the air coming out of the dash vents heats up and ….

Having a similar issue with my 2021 Jayco F53. How did you resolve your problem? Thanks!

Buellah · 06-17-2021, 09:10 AM

It was the sticking valve described above. Taken care of under warranty at Lame’sa RV. Sorry I haven’t replied to this thread for a while, the new RV has been in the shop/storage facility for a month and I just got it back. That’s a whole other story that I won’t get into here. As of my drive home, south Phoenix to north Phoenix, it is working. And just in time!! Temperatures in the upper teens this week and we are hitting the road. Oh, that’s “upper one hundred teens” for those of us who haven’t been to Phoenix in June.

Twohumpsrv · 01-18-2022, 05:14 PM

I also had same problem with 2021 Winnebago Adventure model 29B equipped with big V8. I live in Southern California and AC is essential. AC works fine when idling air gets hot at hiway speeds. Additionally Dash AC makes horrendous noice. Took to Giant Rv Colton Ca for warranty work. Unit was there three months. Went to pick it up and when fixed 10/21 only it wasn’t fixed. Still makes loud noise and unit blows hot air. I read on this forum where at factory during assembly radiator hoses were crossed. I explained to tech and that fixed the problem now get cold air at hiway speeds. However still makes noise. The high heat deformed the plastic plenum which houses the blower fan. I just received word today 1/18/22 parts (plenum) are in, actually I had to call to see if parts were in because Giant RV of Colton will not call you, they are in a sad state and need management to take a close look at their operations. Installation requires disassembly of dash. Original service appointment for repair was August 9, 2021, hopefully I will have work completed by mid February 2022I will advice of updates on repairs.