Dash Air

criscriscola · 04-21-2006, 09:50 AM

I don't know where this belongs, This forum,Workhorse forum or RV Systems.
I have seen posts in the past about Dash A/C not cooling properly. Well after being parked in S Texas for 6 months last winter, when preparing to leave for home, I discovered the a/c was not cooling. I guess unlike an automobile that gets excercised frequently, the M/H sitting for so long is realy detrimental to proper lubrication and keeping the system running properly.
Anyway yesterday I re-charged the system with the proper freon and it started to cool and than fell back. With a therm in the vents and running high cool it would not drop below 80 deg at the vent.
Is this unit a standard GM unit used in GM
Trucks/Pickups or is it modified by Workhorse or Winnebago?
What has previous problems been Seals, compressor, valves?????
Can a Normal automotive A/C shop work on them or does it have to go to GM/Workhorse/Winnebago?
My compressor seems to be working fine and it started to condensate (leaking water)for a little while after charging.
Any help or suggestions will be greatly appreciated.
And oh yes by the way for you folks that leave your rigs sit for any period of time, start that engine and excercise that A/C.
Thanks and happy traveling

criscriscola · 04-21-2006, 09:50 AM

I don't know where this belongs, This forum,Workhorse forum or RV Systems.
I have seen posts in the past about Dash A/C not cooling properly. Well after being parked in S Texas for 6 months last winter, when preparing to leave for home, I discovered the a/c was not cooling. I guess unlike an automobile that gets excercised frequently, the M/H sitting for so long is realy detrimental to proper lubrication and keeping the system running properly.
Anyway yesterday I re-charged the system with the proper freon and it started to cool and than fell back. With a therm in the vents and running high cool it would not drop below 80 deg at the vent.
Is this unit a standard GM unit used in GM
Trucks/Pickups or is it modified by Workhorse or Winnebago?
What has previous problems been Seals, compressor, valves?????
Can a Normal automotive A/C shop work on them or does it have to go to GM/Workhorse/Winnebago?
My compressor seems to be working fine and it started to condensate (leaking water)for a little while after charging.
Any help or suggestions will be greatly appreciated.
And oh yes by the way for you folks that leave your rigs sit for any period of time, start that engine and excercise that A/C.
Thanks and happy traveling

FrontRangeRVer · 04-21-2006, 10:00 AM

I cant remember what brand units that Workhorse uses, but it is NOT a GM brand...Its called climate control or something like that. This is an OEM unit provided by Workhorse. You might still be under warrantee with Workhorse....if so, go to your Workhorse Service center. If not under warrantee, any air conditioner service center can work on these.

Might want to post your question in the Workhorse Forum for better responses....

Kazoo Tom · 04-21-2006, 11:15 AM

Actually most of those units are installed by the coach manufacturer and not the chassis builder. Winnebago (and many others) use Acme brand units(Acme, frequently supplied by SCS in Texas. The Acme plant is in Goshen Indiana. If you open the front of your unit and look at the upper left on the firewall you will see the a/c-heater enclosure.

If you go to the Acme web site they have pages that will show you each unit so you can identify it. In my case it was a cut off thermostat that had gone bad. It senses the temp at the condensor and shuts down the compressor if it gets too cold and begins to freeze. I also had problems with a resistor pack (that controls fan speed) and found the replacement part on the Acme site. I did, however purchase the parts thru Lichtsinn Motors (Lichtsinn as they were cheaper there.

Hope this helps.

Dougmyers · 04-21-2006, 12:15 PM

Any place that works on car or truck A/C,s can work on your A/C.

The problem is a lot of regular garages dont like working on RV,s call around and ask if they work on RV,s and what their shop rate per hour is before you take it to anyone.

Also ask them what their shop rate is before you tell them its a RV and again after you tell them.

bobpie · 04-21-2006, 04:24 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kazoo Tom:
Actually most of those units are installed by the coach manufacturer and not the chassis builder. Winnebago (and many others) use Acme brand units(Acme, frequently supplied by SCS in Texas. The Acme plant is in Goshen Indiana. If you open the front of your unit and look at the upper left on the firewall you will see the a/c-heater enclosure.

If you go to the Acme web site they have pages that will show you each unit so you can identify it. In my case it was a cut off thermostat that had gone bad. It senses the temp at the condensor and shuts down the compressor if it gets too cold and begins to freeze. I also had problems with a resistor pack (that controls fan speed) and found the replacement part on the Acme site. I did, however purchase the parts thru Lichtsinn Motors (Lichtsinn as they were cheaper there.

Hope this helps. </div></BLOCKQUOTE> I am having trouble with my dash air fan speed also. There are 4 speeds which the first 3 run properly but when I put it on high speed the fan stops altogether. Is this the same problem you had Tom? If so just what and where is the resistor pack that you speek of? Thanks for your help in advance.

Kazoo Tom · 04-21-2006, 04:38 PM

Bobpie,

I am not a service tech, and certainly not an expert on a/c, but just got lucky in getting very good advice from the experts here and on other forums. And a lot of trial and error mistakes on my part over the years.

Your problem sounds like it is the high speed fan relay. The high speed relay is seperate from the resistor pack which controls the other speeds. In my case the high speed relay is also attached to the heater-a/c box on the firewall. It is also a very reasonably priced part, simply plugs into the wiring at that location. I don't know for sure how to test it, except to replace it with another to see if it solves the problem. (I'm sure someone will come along here and provide a test for the relay).

My problem (still working on it

) is that I now have all four fan speeds, but the volume of air coming thru the vents at high speed seems woefully inadequate. Nothing like the air volume in any of my cars. Maybe I am expecting too much, but when I put it on high speed, I want HIGH SPEED.

Getting back to your issue - I'm pretty sure it is the high speed relay causing your problem. The only other cause might be a faulty fan switch on the dash, but I would think it would affect all speeds if that were the case.

Feel free to send me a private message, I can take a picture of my setup and send it on to you if it will help.

Retired and Happy · 04-21-2006, 04:51 PM

I had a Georgie Boy a few years ago. Had very poor air volume at all fan speeds. Finally found the previous owner had added carpeting around the front seats and failed to cut out for the return air at the firewall.

chasfm11 · 04-21-2006, 04:55 PM

Tom, a possible reason that you are not seeing the volume of air that you expect is the dampers. Since mine is a diesel, there was separate vacum pump that was used to control the dampers which direct the air. In my case, a couple of the dampers would physically hang up (because of the lack of use) and the vacum pump was too far away from the controls and lacked the power to physically move the dampers.

I corrected the mechanical binds and then had the vacum pump moved closer to the dash. I haven't had a problem with air flow since.

BTW, my dash air system was built by Evans Controls. They have a website with information about their several configurations.

Dougmyers · 04-21-2006, 06:08 PM

High speed relay

You should be able to use a jumper wire and determine if the relay is working.
Pull the relay off and use a jumper in the relay plug in connection with a direct run to the high speed fan if it runs good you know the relay is bad.
The process is just removing the relay and jumping direct to the fan to see if its good or bad.

bobpie · 04-22-2006, 01:50 AM

Thanks for your help Tom & Doug. That sure sounds like the trouble. After all the rain we are going to get today I'll have to check it out.

Kazoo Tom · 04-22-2006, 05:25 AM

In my case I know the relay is working because I do have a high speed, fan works on all speeds. Replacing the resistor pack made a world of difference. As we generally use the roof air (with generator) when it is really hot out, I will probably live with the lower air flow from the dash air (which would not be able to cool the entire coach no matter what I did to it). I will check the vacumn lines to make sure nothing is kinked or leaking. Might be a good project for later today as it is cloudy and rainy here.

For bobpie;

The above photo is of the resistor pack and the thermostat when they were removed from my unit. I will try to get out later and get a photo for you of the locations on the motorhome and post it here. Hope it helps in resolving your issues. Ignore the motorcraft number on the resistor pack, I checked the motorcraft site and the number does not exist, and cannot be cross referenced by any local shop.

Got the photo, this shows the unit as installed.

Open the front, look to the left (behind the rf headlight) yours should look similar to this. The resistor pack is on the left, relay in center and thermostat on the right.

max49 · 04-25-2006, 05:22 PM

Maybe I missed something but the "Hi" speed on the fan runs on a separate fuse. It's not in either fuse panel but is an 'inline' 30 amp blade fuse. Mine is above the fuse panel in the engine compartment.

Robert & Kiki · 04-25-2006, 06:35 PM

I had my MH in the Winnie dealers for almost 10 weeks and they have ordered entire control panel to fix my problem. Problem I have is fan only runs on high speed. According to ACME troubleshooting guide it is the resistor pack on outside firewall! Will check tomorrow to see if this is my problem. Been without low/meduim fan for over 6 months! Thanks for the postings & link to ACME...

Davel · 05-06-2006, 09:24 PM

To Kazoo Tom,
I had the same problem with air flow out of the dash vents. One problem was the floor mat on the passenger side was pushed too far forward and blocked the flow.
The other problem was the routing of the hoses to the dash vents. The one in the middle was ran over the metal support for the dash and was pinched by the dash pod. I rerouted it under the bracket and switched the hoses at the junction so that none of the hoses were pinched off or kinked. It made a real difference on the flow to the center dash vent.

Dave

Gary RVRoamer · 05-07-2006, 07:36 AM

Re Criscriscola's origial query...

The compressor on my 2002 W22 self-destructed when I turned the dash a/c on after it had not been used for about 6 months. The motorhome had been in use but I usually use the house a/c for cooling, so the dash system had not been used since the last time I needed some defogging on the windshield. Compressor seized, parts flew out and the drive belt got torn up (but didn't completely break, fortunately). A Chevy/Workhorse dealer replaced the compressor under warranty but had to get the new compressor from Workhorse - it is not a GM (Delco) part and WH would not autororize the use of the GM part. Dealer has a GM compressor in stock too, but I had to wait two weeks to get a WH part.

Later I found that the heat/cold mixing valve was also broken in the "heat" position, so I still couldn't get chilled air. That's part of the coach body installation and not a Workhorse part. I called some local RV shops and asked who did their dash a/c work and was pointed me to a local a/c shop. Contacted the a/c shop and they were happy to work on the problem, though it took a few days for them to locate a source the necessary part for the mixer.

If you are in the Ocala, Florida area, I can heartily recommend ARA Auto Electric & Air for work on your motorhome dash a/c system.

Robert & Kiki · 05-07-2006, 07:45 AM

I only had high speed fan so resistor pack didn't help. Looking at the wiring diagram there is a relay (on firewall)and that was my fix...! $11

Kazoo Tom · 05-07-2006, 08:46 AM

As Robert said, the relay seems to be the key. It is the object in the center of the picture I posted above. I had replaced the resistor pack and cut off thermostat and all of a sudden I got only high speed. A check of the wiring diagram for the Acme system shows all speed going through the resistor. Replaced the relay ($12 in Michigan, I am jealous Robert) and all is working wonderfully now. Of course my system was neglected by the previous owner ans likely needs a coolant recharge.

spaccman · 05-09-2006, 05:26 AM

Thanks alot Kazoo...tyhe picture you posted is worth a thousand words.I found a PDF file that shows a typical Workhorse HVAC system.....looks like this is a good electrical schematic for the system for future reference. I will change out the relay first.

http://www.utilimaster.com/index.html the GM workhorse chassis Body wiring manual has an HVAC section that looks like the one we are dealing with. -THX again.......-Steve

Kazoo Tom · 05-09-2006, 12:43 PM

The "Workhorse" HVAC may not apply to your motorhome. It will apply to commercial applicatons of the chassis. Winnebago gets the a/c units from SCS or other suppliers that get them from Acme in Indiana. Go to the Acme site (here) and you can download all the wiring and vacumn diagrams.