'02 Mountain Aire A/C questions

[Nurfsmom]

Newly purchased 2002 Newmar Mountain Aire 4095. Got a few questions about dash AC. Blows but not cooling. Checked AC compressor and only getting about 7-8 volts when key turned on and clutch is not kicking in. Also, electrical connection has position for 2 wire plug, but only 1 wire (hot?) It may be grounded elsewhere. Is the 7-8 volts normal or should it be 12 volts? Any suggestions what to check? TIA Nurfsmom

[Lt Dan]

Welcome to IRV2!

There's a great bunch of people here in the Newmar forum to help you with your A/C problems.

[Nurfsmom]

I sure hope so. TY

[Dav L]

Find the low pressure switch and jump it to see if the clutch engages. If so, you are likely low of Freon. If that is so, you have a leak that needs to be fixed. The dryer would be replaced post leak fix, the system would be vacuumed down and then recharged.

There isn't anything weird about the MA dash air. It's just like a car or other RVs. Any decent AC technician can repair and charge it.

[Nurfsmom]

DayL, is it normal to just be getting 7-8 volts?

["007"]

Welcome to the forum.
Down about 1/3 the way down you will find Evans AC dash information.
Your problem maybe covered in the links there, you have small plastic tubing that may have fallen of a connection for control or maybe dried out and cracked as it ages. Within that same link there is other AC discussions and all the links below in my signature will help you with other items in your 2002 coach. SPK64 would be one of them who has same coach his repair section near bottom of first page in QT's #3.
Keep us informed as to your progress, start by looking at the small stuff and it maybe something simple.
Plenty of help here with members having same coach.
Enjoy the forum and safe travels when you do.

[Nurfsmom]

TY 007!

[Dav L]

Originally Posted by Nurfsmom

DayL, is it normal to just be getting 7-8 volts?

Typically no, 7 volts is not normal.
Possible bad ground but more likely bad contacts on an AC relay.

did you try the shorting the low pressure cutoff? That eliminates a zillion common reasons dash AC doesn't work. And takes 5 minutes to do.

[Nurfsmom]

Ok, not being able to find the low pressure switch, after checking voltage on our F350 diesel truck ac to confirm 12v, we bypassed the plug that the wire appeared to be partially broken to achieve 12v directly to the compressor. With this, the compressor clutch engaged. Still no cold air, so hubby charged system with R134A (5-12 oz cans) and still no cold air. This time
(had tried previously), it readily took the freon. Only thing different was the compressor got really hot, hot enough to melt the flexible tubing the power wire was running through .

Not sure what else to try, but did get the name and # of a reputable RV repairman that I will call tomorrow.

Does anyone have a clue as to the proper compressor for this '02 370 ISL Cummins engine. I suspect the compressor has been replaced before. It looks fairly new. Only # I could find was 16FN2887 that was on a bar code on the compressor. Could not cross reference it though.

[Dav L]

You should have a set of AC gauges on the Low and High pressure lines before trying to recharge the unit. Then you will see if the compressor is working or not. I suspect it is. The system may be overcharged.

Before you start shotgunning parts and opening up the system, I would get a qualified auto AC tech to diagnose. You will need to evacuate the system to replace the compressor anyway, and I somewhat doubt you have those tools.

[Xmcdog]

Gauges, gauges, gauges.
Hot compressor. Clean the condenser. Then check your pressures. Depending on ambient temp the high side should be in the 175-250 range. If high for the ambient try running a water hose on to the condense, this will confirm if the condenser is working or not.
The other consideration would be, air in the system. Was it vacuumed before charging?

[Nurfsmom]

Day L, I agree, we should have had the gauges before attempting to charge the system. I also believe it is somewhat overcharged. We've had no luck with finding someone to check out the system. The "reputable" AC repairman I mentioned before did not even return my calls. Others said they didn't have the facilities to work on a 40' motorhome.

Today I did get some additional information of a couple of other places. Will check with them tomorrow. We have about narrowed it down to the expansion valve though, but would rather it be diagnosed by a ac repairman.

We do not have the recovery machine any more, although we did several years ago. Owned our own automotive shop. Wished we had kept that piece of machinery and the tech that ran it.

We are still on the hunt but have found a couple of places that have all the parts we need, including the compressor if need be.

Xmcdog, will do on the condenser. Have also ordered the gauges to be more aware of what is going on. No, it was not vacuumed before adding R134a. We were on the road from FL to MS and just trying to get some cooler, if not cool air going. Not fun running down the road with running generator to use roof air, which didn't help a whole lot anyway.

Will keep you informed as we find out.

[dgapilot]

I’ve got the same problem (no cold air at the dash) on my 2002 MADP 3953. Haven’t gotten to troubleshoot that yet, still working on all the lights!