Chassis AC Not Working

[thrushl]

Ok guys. I need some help.

I have a 2005 Holiday Rambler Navigator with a Roadmaster chassis. The chassis AC is not working. I had it charged, checked for leaks, and the mechanic gave me a little free troubleshooting It seems that the "high pressure side" gets too high. I have no idea what that means, but he said that the fan is not coming on at the condenser. He said it is likely a relay. I have checked everywhere I can think and can't find an AC relay. I found a fuse, but that is fine. Additionally, I have called HR and they were no help. I tried the Roadmaster webpage with no luck.

Any help/ideas where to look is appreciated. I spend over a $1,000 on the information I gave above and can't continue to bleed more while they troubleshoot right now. However, summer is coming and... :-)

Thanks in advance.

[wolfe10]

If you can find out from Monaco who made their A/C components (very few RV manufacturers custom build dash HVAC's), you could contact them.

And, if the condenser fan is not coming on, indeed, you will run high on the high pressure side. Electrically, the relay will be between the fuse and the fan.

[OLDMARINE]

All coach manufactures using car A/c controls. You fill find the relay either on the back of the A/C controls or in the chassis fuse box .

Hope this helps.

Safe travels and God bless. old Marine

[dickandlois]

Just a thought, if the rest of the system is operating maybe the fan on the evaporator is bad.

Have you tested it to see if it is OK. if the compressor is working,thinking that the same relay might power the cooling fan.

Rich.

[rshamilton]

I had a problem like this with my HR. The relay for the condenser fan was fried. On mine 40' diesel pusher it was located on the engine side of the condenser back at the rear of the MH. My AC condenser is hinged on one side, so removing 2 bolts allows it to open outward like a door. This allows easy access to the AC relay and to the engine. The folks at Auto, Bus & Truck air conditoning parts, sales & service in Round Rock, Tx replaced the relay and the fried wired. We also noticed that the compressor side gas pressure was running very high. This is usually caused by a stopped up dryer or expansion valve. In my case a simple dryer replacement and recharge did the trick.

[thrushl]

Hi Rich,

There is no power coming to the fan based on the multimeter.

[dickandlois]

Think I must be sleep walking just noticed your post and reply.

No power to the fan means a bad fuse,size 25 to 30 amps. Location can very ,but most often in the panel under or next to the drivers station. Could be out side on the firewall in front of the driver side.

The most common problem when the compressor runs and the fan does not start is a blown fuse and that is caused by a failed fan motor mounted on the condenser coil mounted out side the coach. Underneath the front or in the rear in the area of the radiator.

If the compressor is working,a good trick is to place a fan in front of the the condenser coil and if the cooling increases, the fan circuit is the one to get working and that should be it.

Regarding the high pressure reading getting to high. That could mean the system is over charged.

Question, gave out some information,but forgot to ask if the compressor starts when you engage the AC?? How in the world did the person charge the system if the compressor does not start?>?>

Could you read the resistance of the fan motor? The other thing is, do you have a battery charger? you could remover the fan motor and power it up that way,if it does not run,thinking its gone bad.

Then the trick is to fine the fuse or relay that powers the circuit. and find a new fan or motor.

Rich.

[wolfe10]

As Rich says, it could be a blown fuse or bad condenser fan motor. But it could also be the fan relay which is between the fuse and motor. The relay is used because you would not want to run the full amp load it takes for those condenser fans through the dash switch. The relay is opened/closed by a signal from the dash switch. When the relay is closed, power from battery source powers the fans. When the relay is open, the fans don't run.

And with the condenser fan not turning, even with a proper charge, the high pressure side WILL be high-- often high enough to trip the high pressure cut-out switch (if your A/C has one).

[retiredblade]

Last year I found my dash A/C wasn't working. It had 134a in it. I went to the engine compartment seen that the wire going to the compressor was unplugged and taped. So, while engine was running, I re-attached the wire, quickly yanking the wire loose because the compressor was frozen up and terrible grinding noise coming from it. So I knew the compressor needed replaced and did so finding the exact one on Ebay brand new at a good price.

Went over to my buddies auto body shop to take the 134a out only to find that it had drained out. Put compressor on, vacuumed the system, put 134a in. No cold air. So I crawled under the front of the coach after pulling the generator forward and found the system was a Evans Tempcon. Found the right block evaporator valve and dryer/receiver, ordered them, got them and today went back over to body shop. drained system, put new parts on, vacuumed system and filled it up and low and behold! Cold air coming from the dash at the right temp! The evaporator valve was plugged with rust, the dry/receiver was plugged with rust, I knew that because I did a postmortem on them, hack sawing the dry apart and taking the evap valve apart, no wonder it didn't work. So doing the work myself I spent approx. $320.

No telling how long that a/c wasn't working before I purchased the coach, I guess the previous owner didn't want to spend money to get it fix.

[johsan38]

Hi newbie.

I never use the dash AC because the coach ( 1998 Diplomat ) is so large it does nothing for cooling in the living area. I run my generator and use the roof airs and keep the whole coach nice and cool. I know the cost of useing the generator is added but useing dash air costs by loading your engine and not getting effective cooling.

johsan38

[hermanmullins]

johsan38,

Welcome to the Forum.

We almost never run the roof airs when traveling down the road. We use our dash air always. What we do is have a curtain behind our seats that keeps the dash air up with us.

We do, however, on really hot days start the generator and turn on the roof airs about 30 minutes before we stop for the day. This way we are ahead of the cool down before we hook up to the shore power.

Hope this helps.

Herman

[wizbang]

Did you get this resolved and if so, what was the final solution?

[thrushl]

Did you get this resolved and if so, what was the final solution?

No, I just gave up on it as it seems everyone just uses the roof acs. With a 45ft MH I figured it wasn't worth the trouble or cost to chase down.

[Bounder2016]

My 2005 Bounder with 8.1 Chevy Workhorse was blowing hot air from dash unit, also making squealing noise. We put it into a shop, they said ac compressor was bad, clutch about to fall off, and all pulleys were bad, they changed compressor, all pulleys and belt for $1800.

Noise stopped, but when I tried ac a week later, it made a loud noise when switch was on, quite when it was off. took back to repair shop, and was told ac compressor blew, and they had to order another one.

When new one came in, they changed it and found that the head pressure was too high, and said I needed a new condenser and they would try and find one and let me know how much more it would cost me. after 2 weeks of waiting,

I called Workhorse and found condenser in stock, but cost $1800. I'm just wondering if the condensers go bad and cause this problem?

I don't have the money to fix it the first time, but having to put out almost $4000 to fix it, will this really fix the problem?

Bounder2016

wfschell@gmail.com

[dickandlois]

Bounder2016,

Welcome to the FMCA forum!

Who and Where did you get it worked on? Think a good AC shop would have found the problems on the first try!

IF the condenser was bad, should have been an issue for them when the system was vacuumed and pressure tested the first time.

Did You run the AC when you picked it up after they installed the first Compressor ???

I think its time to get a second opinion !!!

Rich.

[floydfowler]

Can't locate the ac dryer on my 2001 HR imperial.  Want to change it out while I'm replacing the compressor

[wildebill308]

Welcome to the forum. There are several people with HR coaches and I bet they will have an answer for you soon.

Bill

[dickandlois]

On 7/23/2017 at 1:26 PM, floydfowler said:

Can't locate the ac dryer on my 2001 HR imperial.  Want to change it out while I'm replacing the compressor

Floyd, Yes welcome to the forum. The driers are on the liquid side(output) of the evaporator and before the input of the condenser that is located inside the coach in the as part of the heater unit.

One should check and make sure that if the compressor failed that no small partials of material got in the system, anything in the lines can and will cause the replacement compressor to fail before you want. Flush the system 

Rich.

 

[floydfowler]

Thanks guys.  I found the receiver/drier above the transmission.  Compressor is still running but seems to be leaking at the front seal.  I have recharged it only to have it leak back down and the cooling diminish. I have a new compressor and drier on the way but now I'm searching for the expansion valve as I want to replace it while the charge is out if I can. Need to get it fixed by next week and my wife and I are itching to "get on the road again"!

[dickandlois]

On 7/25/2017 at 2:50 PM, floydfowler said:

Thanks guys.  I found the receiver/drier above the transmission.  Compressor is still running but seems to be leaking at the front seal.  I have recharged it only to have it leak back down and the cooling diminish. I have a new compressor and drier on the way but now I'm searching for the expansion valve as I want to replace it while the charge is out if I can. Need to get it fixed by next week and my wife and I are itching to "get on the road again"!

The fact that the seal failed takes the chances of metal out of the equation in most cases. Regarding the seal failure - make sure when the new one is installed that the proper amount of oil / esters is in the compressor. Some come with oil, some with to much oil and others with no oil depending on the supplier. Also ! Always know the pressure reading on the high side !! To much collent and the pressure goes well beyond the seal design pressure.

If your unit is not providing the cooling point at the ducts in recycle mode and the proper coolant level is installed. There is a good possibility that the expansion valve is failing and that little stinker is located in the evaporator area and it is in the heater / cooling box under the dash. Not the easiest item to replace / let along get to.

Rich.