Dash A/C no cool air

[CapKirk]

My RV is only 2 years old, and the A/C cool air has been getting weaker each year, this year no cool air at all. Found the Low fill side of the A/C unit and hooked up a can of r134a with its gauge, but the pressure shows 85 lbs. That tells me the compressor is not engaging and the unit pressure has equalized into the low side. I looked at fuse's but all are good, I find it hard to believe the compressor our clutch has failed so fast. And on a Diesel pusher its hard to see what the compressor clutch is doing. Is this a common problem if the A/C system gets to low. I wanted to take it in, but everywhere around here is booked 60 days out, plus I will have moved on. Can anyone pass on some experience with this problem.

[Iwannacamp]

Cheap and MAYBE an easy check. Disconnect the coach battery for a minute. New crap will lock-out the compressor after so many short cycles of the compressor... assuming that could be an issue. It could be a variable displacement compressor... then experience is required. I would think any truck service shop could fix it for you.

[njfishing]

Might help if you list the make and model of your RV and the specific engine you have...

[upflying]

A slow degradation of cool sounds like a leak. Compressor wont engage because the pressure switch senses low refrigerant.
I would not use a quicky fix Walmart $20 can of R134a on a diesel pusher, get a professional high/low guage set or let a pro handle it.

[swolfer]

I have a 2014 Forestriver Georgetown 360 XL w/Ford V10 and our dash ac was blowing lukewarm. The mechanic put in more Freon and it was better but not as cold as it should have been. That was almost a year ago.

It has been getting warmer and warmer recently so I went back for another shot of freon. When he was getting ready to hook it up, removing a cap for one of the hoses (lower, I think) there was a "pssst" and he said that there should not have been. He removed a little valve - kind of like a tire valve - and replaced it. He said that it might have been the cause of a slow leak.

He did the freon fill but wasn't happy. He said that the pressure his gauge showed told him the compressor was working, and the temp he measured under the hood was what it should be, but the temp coming out of the dash vents was still too high. And it is. It is better than it was, but it isn't nearly as cold as we get out of our car's AC vents.

He didn't charge me anything and suggested taking it to a specialist. Maybe it is the control that moves the door that divides warm air from heater from cold air from AC - maybe that control isn't working right. Or maybe something is blocking the airflow from the compressor before it gets to dash vents. I don't know.

[Larry-NC]

Originally Posted by swolfer

It has been getting warmer and warmer recently so I went back for another shot of freon. When he was getting ready to hook it up, removing a cap for one of the hoses (lower, I think) there was a "pssst" and he said that there should not have been. He removed a little valve - kind of like a tire valve - and replaced it. He said that it might have been the cause of a slow leak.

That's a Schrader valve. They are similar to the ones used on vehicle wheels but not directly interchangeable.

[swolfer]

Originally Posted by Larry-NC

That's a Schrader valve. They are similar to the ones used on vehicle wheels but not directly interchangeable.

Thanks, Larry. I'm hoping that stopped a leak. But there is still some other problem. The compressor is making lots of cold - under the hood - but that cold isn't getting to the dash vents - despite how close they are.

[CapKirk]

Originally Posted by upflying

A slow degradation of cool sounds like a leak. Compressor wont engage because the pressure switch senses low refrigerant.
I would not use a quicky fix Walmart $20 can of R134a on a diesel pusher, get a professional high/low guage set or let a pro handle it.

I did notice the system holds 2.5 lbs of R134A, written on the Evan’s unit located just above the front generator access slide. At first I thought the solenoid failed to engage the clutch on the compressor, but I was able to manually challenge it and could here it engage. But still the compressor is not pumping when the engine is running. This could be that lock-out issue of the compressor because of short cycles?
But long story short I do think the system needs pumped out, put into a vacuum and tested for leeks, then recharged with the precise 2.5 lbs of Freon. I’ve been hearing the system can be easily over charged, and over lubed, as well creating the same or bigger problems. I’m heading up north close to Canada in a week or two. Should be there for a few months I’ll set up an appointment, I sure thank everyone with their wisdom and experience.

[Larry-NC]

Originally Posted by swolfer

Thanks, Larry. I'm hoping that stopped a leak. But there is still some other problem. The compressor is making lots of cold - under the hood - but that cold isn't getting to the dash vents - despite how close they are.

Okay, here's how it works and some hints of what to look for.

The A/C compressor doesn't modulate. It's either off or full-on. The outlet air temperature is modulated (regulated) by directing some of the air through the heater core--yes, even in the middle of the summer.

There's a flap, sometimes one for each side, that directs some of the air flow through or around the heater. This flap is operated by either an electric motor or a "vacuum motor", a mechanical device operated by engine vacuum.

In your case, it seems like the flap is stuck in the "warm position." (This assumes, of course, that you haven't inadvertently set the control to Heat with the A/C on.) The problem could be a vacuum hose that's come loose, a problem with the control, a bad vacuum motor or electric motor,

Good luck with it. Getting under the dash can be a nuisance. Sometimes you can get good access by removing the glove compartment or radio.