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Topic: Dash Air Problem (Read 901 times) previous topic - next topic

Dash Air Problem

Well, my dash air is not working properly;  output air is barely cool, but not as warm as outside air.  I am curious as to the locations of the components of the system.  Obviously I know where the condenser and fan is located, along with the compressor.  I have located a large assembly under the dash which is encased in a sheet metal cover.  Is this where the evaporator assembly is located, along with the expansion valve?  Can I gain access to this, and how?  Where is the pressure switch located, and where do you put the freon in?  I am assuming that this unit uses R134? (Not doing this myself, just want to know how to locate these components).

Thanks, Mike

 
Mike Brady
'97 U320 SE. #5137
'13 Honda Fit
Willow Springs, MO

Re: Dash Air Problem

Reply #1 –
Getting to those dash components would certainly be a big PITA!  Have you checked the pressure of the refrigerant at the high/low side inlets?  Maybe just a refill would do the trick.  If that is not a fix consider that often the hose connections leading from the compressor to other parts of the dash air system develop leaks.  New fittings can be made locally and pressed onto the hoses.  That was the problem we had with our system earlier this summer.  See "dash air" or "dash AC" posts from earlier in the year.  Dash AC The guy that found our leaks pulled all the refrigerant out (134a) and then filled the system with compressed air.  Then he used a soap solution to find the leaks.  Pretty primitive, but it worked.
The selected media item is not currently available.
George Hatfield

  Never ever use World Line Motors of Nacogdoches for service!

Re: Dash Air Problem

Reply #2 –
It is so inefficient that I took someone's advice long ago and discontinued using the dash air at all.  I just use the generator and one or both roof A/Cs. 
The selected media item is not currently available.Brad & Christine Slaughter
Was:  1990 U280 36'
Was:  2002 U270 36' (With a bathroom door) Build #5981
Is:  2021 Leisure Travel Van Wonder 24RL
2015 Jeep JKU, 2003 S10 QC 4x4 or 2017 C-Max
Lake Havasu City, AZ (or Gillette, WY)

Re: Dash Air Problem

Reply #3 –
On our coach, the R134a is added to the low pressure (suction, blue) port on a hose on top of the compressor, which sits atop the engine. The high pressure port is on the other line right next to it. If I recall correctly, near each of those ports is a pressure switch that will cut the power to the clutch and condenser fan if pressures are out of proper ranges.

Right after we bought the coach three years ago, I added several cans of R134a. I monitored pressures with gauges for R134a as I charged the system. In the three years since then, I think I have added one, maybe two, cans of R134a. The dash cooling system works well. We do supplement with the roof air conditioners when temperatures climb above about 85F.

I've never explored the interior of the metal box concealed in the console at the front of the coach.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: Dash Air Problem

Reply #4 –
I only use the dash a/c while driving, it keeps me plenty happy, I have no idea why anyone would rather run the genset and roof airs instead.  Guess I am missing something again. ?
Also once I was taught how the control knob on dash heat/A/C,/ Defrost really worked, I have been a happy kid, issue was the a/c compressor did not work in defrost mode.  I just had the switch in the wrong position, it is not the defrost position as I thought. One notch back. Now I do not need to run the genset & a/c to remove moisture from windshield, the defrost works great removing the condensation.
Amen & PTL
Dave M

Re: Dash Air Problem

Reply #5 –
As brad said, I gave up on mine long ago. When I got the coach someone had been messing with the high and low pressure switch wiring, got it all straightened out and every thing working as it should. However since we live in Florida and sitting behind that big magnifying glass (windshield) in the Fla sun we always had to run the generator and both roof airs anyway.

But to help answer your question, in the Assembly in the dash are a blend air door and actuator and I believe a hot water control valve that adjust air delivery temp from full hot or full cold. If these are not working correctly (they are vacuum controlled) the air them will be effected. Just a quick tip if you turn on the ac and the compressor is running and not short cycling, the condenser fan is on, and pressures are where they are supposed to be, you likely have a control issue with these valves. Also the vacuum pump for the ac system is behind the entry step cover if someone has not modified it, it is an air powered vac pump and vac reservoir (looks like a fruit juice can) these can cause problems as well for the dash ac controls.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Dash Air Problem

Reply #6 –
Quote from: Dave M –
I only use the dash a/c whiledriving, it keeps me plenty happy, I have no idea why anyone would rather run the genset and roof airs instead.  Guess I am missing something ?
Also once I was taught how the control knob on dash heat/A/C,/ Defrost really worked, I have been a happy kid, issue was the a/c compressor did not work in defrost mode.  I just had the switch in the wrong position, it is not the defrost position as I thought. One notch back. Now I do not need to run the genset & a/c to remove moisture from windshield, the defrost works great removing the condensation.
Amen & PTL
Dave M

Well I just like to be cool, I also run a floor fan blowing up front to help me keep extra cool, but hey thats just me.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Dash Air Problem

Reply #7 –
Interesting. Twice now, after parking for the day, I have been bothered by an intermittent "hum" coming from under the dash in front ot the steering wheel. I knew it must be A/C related, but could not figure what the problem was. Jeff, of course, cannot hear it ... so it is my deal to figure out. I have been able to get rid of it by starting the coach and fiddling with the A/C knobs ... running them through their various positions and fan speeds. Turn off coach and noise is gone.  Hmmm.
Carol & Jeff Savournin
Usta have a '93 U225 36', Usta have a '95 U320 40', Usta have a '02 U320 40'
Usta have a 2006 Born Free, Usta have a 2011 Phoenix Cruiser
Usta have a 2012 Jeep Wrangler Unlimited 4dr
"Your time is limited, so don't waste it living someone else's life."  Steve Jobs

Re: Dash Air Problem

Reply #8 –
Carol, Does Jeff shut down the coach with the dash A/C still running?  We had a similiar sound and i found that if I shut the dash A/C off BEFORE I shut the engine down, I did not get the noise.  Just a thought.
Tom & Bill

2013 Jeep Grand Cherokee

Re: Dash Air Problem

Reply #9 –
Quote from: Carol Savournin –
Interesting. Twice now, after parking for the day, I have been bothered by an intermittent "hum" coming from under the dash in front ot the steering wheel. I knew it must be A/C related, but could not figure what the problem was. Jeff, of course, cannot hear it ... so it is my deal to figure out. I have been able to get rid of it by starting the coach and fiddling with the A/C knobs ... running them through their various positions and fan speeds. Turn off coach and noise is gone.  Hmmm.
Could be vacuum leaking off the system.
1994 U225
build #4514

Re: Dash Air Problem

Reply #10 –
FWIW,
If your AC is running and cooling but not up to snuff, it is probably running low on freon.  It is easy as can be with these new cans of freon with attached guages/hoses/fittings that are sold at auto parts places (and Walmart).  You just attach the fitting to the low pressure port of the AC system and it will read on the guage red, yellow, or green.  I believe you want it in the green area (always read directions).  Seems that all you do is push the button on the container top and fill it up with freon until it is full.  You would do this with the engine and AC running.  This will remedy the low freon issue.  Obviously this will not correct any major issues but for about $35 you can get the AC going again if it is only a small leak.  I did this to mine last year and it has held and seems to work just fine now.  It may leak out again and I will probably just add another can of freon when needed.  My AC is 134 freon and I think all vehicles after about 1992 are 134 freon.  I am not certain of when the change to 134 was done but that is close.
Best of Travels

Re: Dash Air Problem

Reply #11 –
Our high temperature today is predicted at 126.  LOL.  Not that I'm out in it, but our trips start out in the desert, seldom below 80 degrees.  AZ and FL folks are gonna have differnt experiences than some others. 
My first trip to FL in my old U280 was in August of 2000.  I could not believe the amount of water running off the coach with the two ACs going.  Tried to turn one off to give it a rest, but soon realized that I needed both to remain on in order to survive that environment. 
The selected media item is not currently available.Brad & Christine Slaughter
Was:  1990 U280 36'
Was:  2002 U270 36' (With a bathroom door) Build #5981
Is:  2021 Leisure Travel Van Wonder 24RL
2015 Jeep JKU, 2003 S10 QC 4x4 or 2017 C-Max
Lake Havasu City, AZ (or Gillette, WY)

Re: Dash Air Problem

Reply #12 –
Quote
for about $35 you can get the AC going again if it is only a small leak.  I did this to mine last year and it has held and seems to work just fine now.  It may leak out again and I will probably just add another can of freon when needed.  My AC is 134 freon and I think all vehicles after about 1992 are 134 freon.  I am not certain of when the change to 134 was done but that is close.

FWIW
On my 95 U280 it was originally R12 but was converted by the original owner to R134a prior to my ownership 10 years ago.
Gary B
 

Re: Dash Air Problem

Reply #13 –
I spent a week in Laughlin NV when it was 127 at the LAKE. We camped in a tent and the candles inside melted.
Blew an AC line on my CJ7. Took the doors off and it was like driving with a hair dryer in your face - and I GREW UP in Tucson! We left at midnight to head up to Washington State and it was 109 (cold wave)...
The selected media item is not currently available. Dave Head & Megan Westbrook
Titusville, FL - The Great Outdoors
'98 270 buying this month
Toad is a 2018 F150 XLT