Resolved Dash A/C not blowing cold air

[Neal]

Brought coach out of storage finally for next trip after 8 months and I don't think the dash A/C is blowing cold air. Recirc etc. Any suggestions in anything I can check? Fuse bay shows all good. 6 years and fine until now. Next Gaffney visit is November.

 

[B52Bombardier1]

Does the AC compressor clutch engage when you turn the system on?

Rick

 

[J&JD]

Were you part of the PDM module Recall? That was one of the known effects of a defective unit.

 

[Webz]

I'm on my 3rd dash AC compressor. As asked earlier, does the clutch engage when turned on?
Do you have gauges to check the freon level? Could be a leak in the system.

 

[Neal]

I had the PDM recall done (twice I think), thanks for the info, I'll put a call in to FL next week.

Where do I find the clutch and what do I do if it's not doing what it's supposed to do?

I do not have the equipment so I'd pretty much have to take it somewhere. I can obviously use the house AC's and I'm scheduled for Gaffney in November so I can get it squared away then. I'm hoping it is just gooked for now somewhere and during some travels ahead it clears itself, or maybe there's a leak. Who knows.

 

[B52Bombardier1]

The AC compressor will have two black hoses sticking out of it and its mounted to the motor with a belt around a pulley on the front. My suspicion is a refrigerant leak and your low pressure cutoff switch is stopping the compressor from engaging - low refrigerant means no oil to the compressor . . . bad.

Don't use sealant in a refrigerant can to fix this!! Sealant contaminates the recovery machines in the professional AC repair shops and those people will DESPISE you. Though, I do recommend the use of UV light dye in the refrigerant to help detect leaks.

Let's hope its not a leaky evaporator or condenser. Maybe just a hose fitting o-ring leak.

Rick

 

[Neal]

Any FL shop can fix this or wait for Gaffney?

 

[Rich W.]

Here’s some interesting reading while you ponder this:

https://newpar.newmarcorp.com/instance1Env99NEWMAR/html/images/SS2013EVEQUILTRAIN.pdf

RV Air Conditioning Service

Servicing your dash air doesn't have to be difficult. In this article we examine how to test, troubleshoot and recharge your RV's air conditioning system.

www.rvtechmag.com

Newmar Dutch Star Diesel Freightliner Chassis Dash A/C

I have a 2000 Dutch Star Motorhome built on a Freightliner Raised Rail Chassis. The Dash A/C does not work. Blows hot air after engine warm up. The Vent function blows Hot air as well. Currently running generator and roof air while traveling. Having trouble getting someone to work on coach. They ...

community.fmca.com

I’m not very familiar with DP dash AC systems but I should be, and your post got me thinking. I’ll be interested to hear your findings on this one. The many links in the third post in the FMCA link are a good resource.

The problem with leak detection is the 40’ run from your dash to the compressor. Also this means that you system takes a lot more refrigerant than conventional automotive systems. But you can see the compressor from the door side rear compartment so the first thing to check is whether or not it is engaging when running and calling for AC. If you are just seeing the pulley spinning but the center part isn’t engaging, you are probably low on refrigerant. The question then would be why which as I said on these things could be difficulty to identidy.

But the charge ports are easy enough to get to (upper pass side corner under the front hood) so you could just start adding refrigerant (up to 5lbs or more) until the compressor comes on (or doesn’t). As I said I’m no expert here but I’ve done a lot of “standard” auto AC recharges. And in most (if not all) cases, ultimately there was a leak involved.

If you decide to try a recharge to see what happens, this is a good little primer on the subject:

https://www.autozone.com/diy/climate-control/how-to-recharge-car-ac

AC compressor (hard to get to but easy to see)

Refrigerant ports (upper passenger side front)

Cheap one-gauge AC charging gizmo (avail at any auto parts store, usually included with purchase of a two 1lb can kit)

If you add 4lbs or so and the compressor starts kicking in, you know it was low, just not exactly why. But if its a really slow leak, that may get you through the season.

 

[Neal]

Great info, thank you.

 

[osuallen]

We had a thermal switch at the evaporator go out this spring that kept the compressor to engage. it also prevented the engine go into high idle -- weird.

 

[B52Bombardier1]

Any competent shop should be able to do this job unless this is a warranty job. The leak needs to be found and fixed and then the system evacuated down to a hard vacuum. And see if it can hold this vacuum with the vacuum pump turned off for at least thirty minutes. Pulling a hard vacuum removes all air and all moisture from the system - neither of which cools your vehicle.

Consider changing the receiver-drier and /or the accumulator, if equipped.

Cross your fingers that you are running R134A refrigerant and not the new stuff - R1234yf. Given how large of a capacity your AC system seems to be, you will be scanning the horizon for a bank or a liquor store to rob to pay for this repair.

Rick

 

[lostinfla]

While on our trip in '21, we had the compressor go out up in Boardman Oregon (about as far from home as possible). The compressor locked up and shredded the belt. The engine overheated and alarms went off as the engine shut down about 500 ft from the entry to the campground. I had an extra belt but the compressor had melted the clutch assy and wouldn't be usable to run the belt. My wonderful wife, a former parts manager at an auto dealer, got on the phone and found Freightliner Northwest in Hermiston about 15 miles away. They had a new compressor in stock with clutch and the price was only 200.00!! She took off in the toad and picked it up. 105 degrees that day combined with a very hot engine and not really enough correct tools made this a bear to change out, but I finally got it done using the bike rack as a tool bench. Didn't get the air repaired until our trip to Gaffney as the system had to be flushed, evacuated, and recharged with a new dryer, but at least I could fire up the engine with the belt running the other accessories. That fence in the background is the campground entrance. The joys of RVing....

 

[Neal]

Wow! Glad that one worked out for you and you have the know how. The hardest part as we all know in planning for trips is trying to fit in unscheduled service. Now the question is when/where or wait for Gaffney in Nov.

 

[Neal]

Anyone ever used Love's or something similar for service? I wonder if they could handle something like this?

 

[Rich W.]

Anyone ever used Love's or something similar for service? I wonder if they could handle something like this?

If fhey service trucks then they should be able to handle it, but I’d be much more inclined to go to a Freightliner service center. I have a good one an hour or so from here (Sacramento) that I use for any chassis stuff I can’t or don't want to do myself. Their labor rate and parts prices are reasonable and I know they are competent.

 

[Neal]

I found a FL service center enroute to my first stop I'll see if they can fit me in. When getting into aircraft ownership I learned of a term, a thing - "maintenance induced failures" aka MIF's as they are called. We all know it's true and as such I'm really skeptical of making matters worse. I had a situation with my plane recently trying to get an inspection done and they obviously didn't know how to do the job and I told them, if you don't know how to do it, please say so, I don't want any problems, and they backed out of trying to do the job they couldn't which was good. So I'll go into something like this situation with the same caution, give them an opportunity to look and assess and go from there and if I don't get a good vibe I'll pay up and continue on my way. Even if it's a shot of refrigerant that may leak but at least get me through two months of this trip.

How do we know what refrigerant is used in a system such as this? I'll likely put in a call to Gaffney Monday.

 

[Rich W.]

I found a FL service center enroute to my first stop I'll see if they can fit me in. When getting into aircraft ownership I learned of a term, a thing - "maintenance induced failures" aka MIF's as they are called. We all know it's true and as such I'm really skeptical of making matters worse. I had a situation with my plane recently trying to get an inspection done and they obviously didn't know how to do the job and I told them, if you don't know how to do it, please say so, I don't want any problems, and they backed out of trying to do the job they couldn't which was good. So I'll go into something like this situation with the same caution, give them an opportunity to look and assess and go from there and if I don't get a good vibe I'll pay up and continue on my way. Even if it's a shot of refrigerant that may leak but at least get me through two months of this trip.

How do we know what refrigerant is used in a system such as this? I'll likely put in a call to Gaffney Monday.

there will be a sticker in plain view identifying the refrigerant type. This is mine (R134a):

 

[Just George]

@Neal Hope FL works out for you. I had Premier Truck (FL Oasis) check the AC when we first got our 22 but they only needed to adjusted freon level. I also had the AC system rebuilt on my 15 Ventana due to a compressor failure. I used Texas Truck AC which I would recommend if your are near Dallas. Posting this mostly to let you know there are companies the specalize in truck & commercial vehicle AC systmes. If FL dosent work out you might look for a company like Texas Truck AC near your travels.

 

[Kevin D Pem]

Now that the fear mongering has slowed!
1. Low charge ( although you can have a leak, (think balloon, may just be a hose penitration, no fix, just charge)).
2. Low pressure switch ( simply replace switch, can be a DIY project)
3. Broken wire to the compressor clutch.
4. Failure of clutch.

I have had all the above, over the years. Short of a breach of the system ie. accident that invaded the integrity of the system, or a failure of the compressor, I have not had to evacuate a system. Charge kits and freon are available in auto parts stores. All the fill ports can't be interchanged, meaning you can't make a mistake, as the fill hose will not fit onto an incompatible system. The switch has a valve that keeps the freon in the system while changing it out.
Checking continuity on the clutch wires will clear the possibility of a broken wire.

All in all, a competent service technician shouldn't have 1 hour finding the problem...

 

[Joe Hogan]

The A/C compressor looks something like these images (see link).
The clutch. where the belt drives pump, attaches belt drive to the compressor body.
You need A/C specific tools to measure pressures, evacuate and fill these units.
These units are typically on the accessory end of the Engine, where the accessory belts drive Power Steering, Alternator, A/C, pumps.

www.acpartsguys.com - RV & Motorhome Compressors