Community Forums

FullAstern · 06-15-2007, 11:22 AM

Ok, the dash air is totally dead on my P32. It was working fine and now it's not. It blows hot air as if it were on heat. Not even a bit cold. Is there a fuse or relay that controls this? What should I check first?

FullAstern · 06-15-2007, 11:22 AM

Ok, the dash air is totally dead on my P32. It was working fine and now it's not. It blows hot air as if it were on heat. Not even a bit cold. Is there a fuse or relay that controls this? What should I check first?

Redlands Truck and RV · 06-15-2007, 01:05 PM

If you can confirm correct operation of the AC compressor (does the clutch engage and stay on?) have your service center restrict the flow to both hoses at the heater control valve as a test.

We have seen heater control valves allowing hot water to migrating into the heater core even though the valve is off. This hot water overwhelms the cold air coming off the evaporator.

Richard 34A · 06-15-2007, 02:19 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by FullAstern:
Ok, the dash air is totally dead on my P32. It was working fine and now it's not. It blows hot air as if it were on heat. Not even a bit cold. Is there a fuse or relay that controls this? What should I check first? </div></BLOCKQUOTE>

Is the a/c compressor actually engaging when the motor is running? If the Freon gets too low, the compressor won't engage / cycle on and off...

Wallaby Dan · 06-15-2007, 04:12 PM

FullAstern, There should be a peep sight on or near the air dryer {it should be aluminum about 4" in Diameter and about 12" tall. There should be a couple of wires running to that same air dryer. If you, and I think it does, Have R-134 freon in it you should see some bubbles in the peep sight and if nothing is happening, Unplug that two wire plug at that switch and jump the leads and if the a/c comes on the freon is low and needs recharging. Or you may have a leak or something. If you can do that yourself fine but if you have never done that I would take it to someone that services a/c systems.
You didn't say what year model this coach was or model rv it is. But they have used R-134 since 1994, And a lot of the older units have been converted over to R-134. If You can find the places for the hose to connect a can of Freon to It should have a blue cap on it and a red on the high pressure side.You can buy R-134 and a hose to connect to the low side[Blue cap] and add the freon. If you jump the two wires off that switch and nothing happens, could be a fuse and or compressor problem and I would take it to a dealer for repair.i don't know how much mechanics you may have done, so if in doubt, Take it to the shop! Hope it is a easy fix, Capt.Dan

Full-Timers · 06-15-2007, 06:10 PM

After the engine is warm, feel both hoses going to the heater control valve, also known as the Evans Valve. If they are both warm, the valve is bad. This is a common thing. This valve is designed to cut off the flow of warm engine coolant to the heater core when the heater temp control is in the cool position. Many of these valves have failed in the heat position.

TakerEasy · 06-16-2007, 05:41 AM

On the Heater control valve, there are several ways to check it.

1) When the engine is cold, and you start it, does the dash ac blow cold at first then warms as the engine warms?

2)Pinch off the lines to the heater control valve and see if it helps.

3)On the newer heater control valves (evans) they have a bypass port so some water always flows to and from the valve. So if you use the feel method be sure to feel the lines between the valve and evaporator.

Folks here gave you some pretty good tips in order to move to the next step.

1) Is the compressor running?
2) If so, what does the sight glass look like?
3) Heater control valve.

Compressor not running?
1) Does it have enough refrigerant?
2) Temporarly jumper the low pressure switch and see if it cools. They are known to go bad. If it is Bad, always replace it with the proper one. Auto parts may try to give you a look a like, and some of the older Chevy motorhomes had expansion valves instead of orifice tubes. It makes a difference.

Try to get some more info and let us know.

max49 · 06-17-2007, 04:32 PM

Check to see if it's really dead while driving. I've thought mine died a few times including this weekend.
I don't know what kind of AC systemm WH used on these but it's not one to be coveted by others. Mine will absolutely not get cold or even cool , just plain warm, if I'm idling or stuck in a traffic jam or going very slow. It's terrible in those circumstances.
But as soon as I start6 moving along , it gets acceptable but not nearly as cold as my 4 other vehicles.

Full-Timers · 06-17-2007, 07:07 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by max49:
Mine will absolutely not get cold or even cool , just plain warm, if I'm idling or stuck in a traffic jam or going very slow. It's terrible in those circumstances.
But as soon as I start6 moving along , it gets acceptable but not nearly as cold as my 4 other vehicles. </div></BLOCKQUOTE>Try running it on Max. While not on Max it sucks in hot air from inside the engine compartment. In Max is gets cooler air from inside the coach.

max49 · 06-18-2007, 01:22 PM

I always run the AC on max. in all my vehicles.
Why does your guys get cold at idle or traffic jams?
This is another thing that a WCC svc cntr has looked at on mine, but they could'nt / would'nt, did'nt fix it because it starts to get cool when you start driving.
I thought it was just typical WH AC.

DriVer · 06-18-2007, 03:42 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by max49:
I thought it was just typical WH AC. </div></BLOCKQUOTE>Max, Don't forget about half of all your AC components are Damon.

FullAstern · 06-18-2007, 04:17 PM

I believe TakeEeasy has nailed it. When first started, it tries to blow cold, very quickly it starts to blow hot...

depchief · 06-18-2007, 04:27 PM

On a recent trip the dash air worked fine while on the road running at speed. high 80's outside, 48/49 degree cool air at center outlet. Recorded with a HVAC digital thermometer. When we slowed in traffic or at the fuel stop the air went from cold to hot. recorded up to 85 degrees and higher at fuel stop. This is something I have to check, the heater hose has a valve installed and the hot water should not be passing. Will have to get the laser thermometer working on the lines. Also have to make sure the electric fans are working properly.

DriVer · 06-18-2007, 04:44 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by depchief:
Will have to get the laser thermometer working on the lines. </div></BLOCKQUOTE>DC, You can borrow mine when I get back.