Chassis A/C not working from Dash

[Jim Godfrey]

RSR Rail Chassis 2008 Holiday Rambler Vacationer XL.

Before I start to look and learn about this system, can anyone share there experience with AC not working on this model? Fuses? Any simple troubleshooting steps? Is the Compressor on the Diesel Engine and is there a Clutch I can see if it works or not?

I want to check the simple things before I take it to someone.

[l1v3fr33ord1]

Jim-

What specifically does not work? For instance, does the fan work? Does it blow cold air, but only on the defrost setting?

[TonyMac]

My compresser is mounted low on the driver side of the engine. And it has a clutch.

[Jim Godfrey]

Originally Posted by l1v3fr33ord1

Jim-

What specifically does not work? For instance, does the fan work? Does it blow cold air, but only on the defrost setting?

The heat and ac controls work meaning that I can adjust the floor, defrost face level controls. The temp control works to add heat to warm all the way to cold to receive outside air temp.

When I put the control on AC, MAX, AC or Defrost, and the temp control are all the way to cold, the temperature of the air never gets colder than the outside air.

I did not check the AC clutch and I did not take my IR temp reader to the evaporator system on the roadside of the coach.

[Jim Godfrey]

Update: After testing, the AC compressor is not coming on. Maybe a fuse, maybe low pressure. Can I charge this system like a car? where do I do it?

[TonyMac]

Originally Posted by Jim Godfrey

Update: After testing, the AC compressor is not coming on. Maybe a fuse, maybe low pressure. Can I charge this system like a car? where do I do it?

On my DP, the charging ports are up front in the Genset bay. And yes, it charges just like a car, because the system is just like a car, just more hose. I'm not sure what pressures you'd be looking for.

The dash air will never be enough to cool the rig. Some folks never repair theirs, choosing to rely on the roof air/generator instead.

[Jim Godfrey]

Thank You for the information. I understand that it will not cool the whole rig, I want to get it working. I am going out to look to see if it is a low-pressure issue. Maybe I can get the compressor to come on after a can.

[RobRoy]

Originally Posted by Jim Godfrey

Thank You for the information. I understand that it will not cool the whole rig, I want to get it working. I am going out to look to see if it is a low-pressure issue. Maybe I can get the compressor to come on after a can.

I would highly advise to not just add a can of refrigerant to your system for many reasons.

First I would purchase a set of inexpensive a/c gages and connect them to your a/c service ports both high side and low sides…the service ports will be different sizes so that you cannot mix them up.

Once the gages are hooked up, I want to know the pressure readings both High side and the Low sides not running ( static) the pressure should be equal on both sides and should be close to ambient air temps ie: 80 deg = @ 80psi

Once you know the pressures report back here with them and the folks here will get you thu the next step in your diagnosis to get you’re a/c going.

Adding refrigerant may be the “ Silver Bullet “ guess and get your a/c running and that’s cool in more ways than one ……but the down side is if that is not your problem? You now have to evacuate your overcharged a/c system and start from scratch.

To find you’re a/c ports first look on the back of the a/c compressor they may be there…if not?......follow each of the lines from the compressor with a flashlight and you will find them with a little looking …my coach is different and not the same as yours.

Again buy some gages... there cheap but are priceless to have when servicing and diagnosing you’re a/c system.

https://www.amazon.com/s?k=a%2Fc+gag...f=nb_sb_noss_2

Hope this made some sense

Happy Trails

[Doug.terri5]

Jim,

I have a 2008 Monaco Diplomat and I'd recommend a couple of really quick checks after you confirm you have Freon. first, by the low pressure port you'll find a low pressure switch. Jump across the 2 wires and see if it works and blows cold. Next you'll find the temp sensor going into the evaporator. You can also jump across this and see it it has gone bad and remaining open. Both of these items do fail rather frequently.

Best to you.

[tomclayton1]

'04 HR Ambassador, 8.3 ISC. 'Local Joe' added some Walmart freon bottles and overloaded the system with oil. I had a real A/C technician come out to fix it and it's expensive. Compressor - $350, Dryer - ??, Freon - $200, labor - $125 service call plus ?? hrs at $145. Looks like $1500 to $2000 when it's said and done - still waiting on parts.
There is no 'silver bullet'. These systems aren't made to sit for months/years with no action. I had to run the generator all day and still couldn't get enough cool to the front to overcome the heat that came though the windshield. I know why people don't fix these systems, $$$$, but the alternative was not acceptable to us, plus our generator cuts out at 3/8 fuel level and you're left with nothing.
Hint: Regular maintenance by a real a/c technician & run it for 30 min every month (minimum).

[Jim Godfrey]

Hi everyone. Thanks for the advice and I am reading all the information. I fully understand why I shouldn't just add a can and see what happens. Also, I have friends in the business and they will be able to help me too, but I wanted to test the basics before I go see them and wanted to bounce this effort of this great forum.

I don't have a full set of Gauges, but I do have a can gauge and can check the low-pressure side. The static pressure was around 40# on the low side. Because I saw some pressure, I assume the compressor is not coming on because of another reason.

I like the idea of jumping the switches for a moment to see if it is related to that.

Does anyone know if the system is fused on one of our many panels?

I am going to spend some more time on this today while I am at home. I am going to look for a chassis schematic too.

Maybe I should just jumper the clutch switch on the engine to see if the compressor comes on at all. The clutch could be rusty and broken?

[l1v3fr33ord1]

Jim-

I believe some of the schematics Myron ("YC1") supplied in this post may apply to your coach.

[RobRoy]

Originally Posted by tomclayton1

'04 HR Ambassador, 8.3 ISC. 'Local Joe' added some Walmart freon bottles and overloaded the system with oil. I had a real A/C technician come out to fix it and it's expensive. Compressor - $350, Dryer - ??, Freon - $200, labor - $125 service call plus ?? hrs at $145. Looks like $1500 to $2000 when it's said and done - still waiting on parts.
There is no 'silver bullet'. These systems aren't made to sit for months/years with no action. I had to run the generator all day and still couldn't get enough cool to the front to overcome the heat that came though the windshield. I know why people don't fix these systems, $$$$, but the alternative was not acceptable to us, plus our generator cuts out at 3/8 fuel level and you're left with nothing.
Hint: Regular maintenance by a real a/c technician & run it for 30 min every month (minimum).

Hello Tom, for clarity purposes me referring to a “ Silver Bullet “ what Im referring to what are known repeated pattern failures as we seen in many of the same type systems whatever that system may be and that they can be very helpful to a quick resolve.

As a matter of fact IMC most people posting here are looking for are pattern failures “ Silver Bullets” to get them headed in the right direction of finding a resolve to a pending issue.

ie: I have water running under my floor by the sink and don’t see any leaks under the sink?

A common pattern failure would be something a like the flex drain hose in the wall that breaks or separates in the slide out “take a look in this place” and if so? We have a “Silver Bullet”

Sorry to hear about local Joe Jacking up you a/c system and seriously overloading your system with oil.


Sounds like you next choice and hiring someone a little more knowledgeable.
In a serious overdose of oil situation where you now have slugging issues and performance issues, in the past I have flushed these systems with conventional a/c flushing equipment with very limited results of removing massive amounts of oil.

There is some a/c equipment out there to flush a/c systems that you hook up and flush with that uses hp pressure pulses and filtration ……… very very rare to find someone with this type system due to ROI is cost prohibitive

Another method In the past I have used is high pressure dry nitrogen and loading the system to 300psi and then tried to bleed off some of the oil from the system doing so with limited positive results.

Having serious excess amounts of oil in the a/c system, a major portion of that oil migrates to the low points in the system such as the bottom of the condenser, the bottom of the evaporator and the likes of including some of the components your placing and it lays in there with no way to get it out ….other than removing the contaminated component draining the excess oil and flushing the component.

As far as a need to run a mobil a/c system monthly? …… it cant hurt …but certainly is not needed.

Both new and used cars sit on car lots for months even years at a time with no issues….,mobil a/c components, oils, and seal technology have come a long way since 1968 …thankfully.

Good luck with your new a/c service professional and hope he brings you some joy.

In most cases the only gripe is with hiring top gun service professional to do the job is the price$$$$ ……… and things can certainly be way worse than that… as you have already found out.

Happy Trails

[Jim Godfrey]

I have performed some more troubleshooting and wanted to share. I had some pictures, but my phone did not sync with the google cloud yet.

Upfront I found two switches, a thermocouple, and a pressure switch. Each one was closed. After starting the engine and taking measurements, 12v was passing through each closed switch. This was telling me that there was no problem upfront and the signal was being sent to the rear.

I went to the engine. I could not turn the compressor by hand. I started the engine and discovered that 12v was not being sent to the clutch on the compressor. Because it is so close to the alternator, I jumped the wite to make it hot to engage the clutch. When I did, I heard the clutch engage, but it sounded like slipping brake pads.

My conclusion is that I have a blown fuse or relay somewhere because either the clutch or compressor is bad.

Time to take this to my experienced friends. At least, I know where to have them focus without wasting much time.

I will follow up at a later time.