Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > THE CHASSIS CLUB FORUMS > Freightliner Motorhome Chassis Forum
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 05-12-2022, 12:22 PM   #1
Senior Member
Toribk's Avatar
Join Date: Oct 2011
Posts: 588
Dash AC Woes

Well, I've got something strange going on with my (Denso)dash A/C unit and admittedly, it is my weak point as far as knowledge is concerned.

Leaving Savannah, GA this morning my dash AC was working fine as we packed up and departed and about 10 miles into the trip south to head home, it stopped blowing cold air and was blowing the ambient air temp from outside.

Waited about 30 minutes and switched it back on again and it started blowing cold again. The co-pilot stuck a thermometer in the dash vent and it hoovered between 45 and 55 degrees underway.

It remained at those temps for another 30 miles and like before, began blowing ambient air from outside?

We continued to our current overnight stop here in Jacksonville, Florida and when we arrived, I turned on the dash AC again and it was blowing cold air as expected. The condensor fan was running as we sat idle and I could here and see that the compressor apperared to be functioning as normal with the clutch engaging?

So, for you gentleman that have a broader knowlege base of RV AC systems than I, what do you feel the issue might that is generating the symptoms I'm experiencing.

Thank you for your input. I have the Denso RV AC Manual with me on pdf to refer to.
Toribk is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free! RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 05-12-2022, 12:40 PM   #2
Senior Member
Skip426's Avatar

Join Date: Apr 2011
Location: Powell River, B.C.
Posts: 25,859
So your Denso dash section of the A/C unit was installed by your coach manufacturer .
Freightliner installed some sections while building your chassis ; compressor ,condenser, and pressure hoses from the engine to the front of the frame rail where the hose to the dash unit attach.
As per the diagram from Evans /Tempcon.

From your description of the issue ,two possibilities;
1; the refrigerant pressure in the system is right on the border line of being low and a slight top up is required .
2; the evaporator is freezing up , and has to thaw before proper operation can continue.

I have the Denso pdf and will read through and post anything else that comes to mind.
Attached Thumbnails
Click image for larger version

Name:	Evans Parts.PNG
Views:	13
Size:	274.5 KB
ID:	365290  
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
Skip426 is offline   Reply With Quote
Old 05-12-2022, 01:58 PM   #3
Senior Member
Join Date: Aug 2020
Location: Ohio
Posts: 1,274
If you have not worked on a/c systems.. if you are in Florida.. they should understand a/c better than anyone.. so hit a shop in Florida and get system checked out..
Or.. you can go into a/p store and get a book on basic automotive a/c repair.. it will save you a lot of money.. even if you let shop repair.. you can read up and understand if shop is just ripping you off.
Get a can of Freon and with low side gauge and try to top off.. for less than 30.00
A/c is not too hard to understand... if you got a book.. the book will give the correct pressure for air temp.. and get you close..
I would think that the state of Florida should have best a/c techs in the world... because they do it down there every day..
Good luck and keep us posted
2000 southwind storm, workhorse custom chassis with 7.4l vortec
donr103 is offline   Reply With Quote
Old 05-13-2022, 01:32 PM   #4
Senior Member
Toribk's Avatar
Join Date: Oct 2011
Posts: 588
Thank you both for your responses.

I am waiting to arrive back home on Sunday before looking into the problem further, but I'm beginning to THINK I may have a relay going bad.

Today we drove from Jacksonville, FL to Ft. Pierce and the dash A/C worked fine the whole trip..........puzzling?

I intend to put a guage on the low pressure port to see if it is in fact low on R134A and if so, have a reputable AC tech come out and service it in lieu of filling it from a store bought DIY product.

It is my understanding and experience that RV dash AC systems are a bit more complex
and I certainly don't want to compromise the compressor, surpentine belt and possibly other components should the compressor fail (ie. sieze) from overfilling it...........especially underway.

Although you would think South Florida would be home to a number of AC Technicians, very few shops will touch an RV because it usually involves dismantling the dashboard to troubleshoot and/or fix a problem. They have plenty of work with vehicles.

Anyway, I'll jump off that bridge when I get to it.

Thanks again.......will keep you posted.
Toribk is offline   Reply With Quote
Old 05-13-2022, 04:54 PM   #5
Senior Member
Join Date: Aug 2020
Location: Ohio
Posts: 1,274
So glad it all worked out for you.. have safe trip.. all the a/c I have seen.. if you ever need to get into dash.. is just 2 wood screws.. access is through area by pass side feet.. there is a kick plate.. 2 screws you find with magnet.. then pull kick plate out.. many times there are cigarette lighter or 110v outlet.. just unplug them and you are there.. you can get access to everything.. maybe takes 30mins.. you can check you door motors.. lube cabes.. and HVAC actuator rods.. and check relays.. bet you need to clean blower resistors pack..
Good luck and keep us posted
2000 southwind storm, workhorse custom chassis with 7.4l vortec
donr103 is offline   Reply With Quote
Old 05-14-2022, 09:28 AM   #6
Community Moderator
Petro's Avatar

Winnebago Owners Club
Freightliner Owners Club
Join Date: Dec 2003
Location: Weyauwega, WI US
Posts: 7,815

If you look at the diagram posted by Skip 426 you will see the control system is vacuum operated. You will see a vacuum pump and vacuum ball & the control. Rubber hoses are attached to these controls The hoses have been known to crack where they are attached as they age.

Over the years I have had that happen to me a couple of times. If your problem persists I encourage you to check the connections for vacuum leaks. If you find a crack and you have ample hose a quick fix is cut off the hose by the crack and reattach the hose.

Good luck;
Don & Bev Morgan Weyauwega WI, 05 Itasca Horizon 40KD, 400 HP Cummins, Adopted by a great couple, Toad 07 Saturn Vue AWD, Air Force One, TST 510 TPMS, Mayor of Weyauwega 2007 - 2013, Waupaca Co Board Supervisor 2010 - 2014
Petro is offline   Reply With Quote
Old 05-15-2022, 07:35 PM   #7
Senior Member
Join Date: Aug 2015
Posts: 807
I would suspect vacuum control or your hot water valve
Wild Card is offline   Reply With Quote


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Blower Woes, Dash AC/Heat Fan RVNeophytes2 Monaco Owner's Forum 7 04-15-2013 03:05 PM
Dash Display Woes roger1938 Workhorse and Chevrolet Chassis Motorhome Forum 23 12-11-2010 12:17 PM
97 Itasca Suncruiser - P30 w/ AutoPark woes AutoParkH8r Workhorse and Chevrolet Chassis Motorhome Forum 4 02-21-2009 05:18 AM
Master cylinder woes fixed!! HarveyP MH-General Discussions & Problems 4 02-07-2009 08:12 AM
generator woes crazy jim MH-General Discussions & Problems 65 10-29-2007 06:36 AM

» Featured Campgrounds

Reviews provided by

All times are GMT -6. The time now is 08:42 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2022, vBulletin Solutions, Inc.