Dash AC kaput!

[Roscott]

Need some help trying to figure out where to start looking in to this. Dash AC does not blow cold air. I've searched the forum and did the troubleshooting related to the heater hose/valve issue letting warm coolant continually flow, to no avail. When I checked the compressor a couple things didn't look right (I am no auto AC expert....I basically know nothing). In the first picture, when the ac is 'on', shouldn't that disc/clutch on the front be turning? It turns freely, by hand, whether ac is in 'on' or 'off' position. It does not turn when engine running and ac in 'on' position. In the second picture, I found this wiring and harness coming to the compressor. Although 2 wires go into the connector on 1 side, only 1 wire comes out and connects to the compressor. I assume this is a ground, but not sure if the other is needed. It looks like it was cut, but not sure if intentional. Any guidance is appreciated before I try to take it in and have a shop 'rake me over the coals'. I know there has to be someone on this forum who's an expert with these systems.

Sorry the pics are sideways....not sure why this happens on here sometimes.

[Skip426]

The wire is the power for the electro-magnetic clutch that drives the compressor. If there is no power to the wire then low refrigerant is a possibility, The refrigerant carries the compressor lubrication oil so it shuts down to protect the system.You'll have to get to the front of the coach and check for power through the two controls there.
Thermostat sensor and low pressure switch.
I'll dig up pictures and re-post.

[Skip426]

Here's some of the info I have on our A/C systems and one photo, showing thermostat. Looking for picture of low pressure switch. Windows 10 re-organized my photos

[Roscott]

Thanks Skip! If I'm low on refrigerant (I can check that, not sure why I didn't think of it), doesn't the compressor need to be running in order to fill?

[siggyd]

Looks like you are low on refridgerant, that would explain why the clutch is not pulling in. Check /see if the Low refridgerant sensor is a closed contact.
eg 12volt on both sides when AC is ON.
Here is a link to "Evans Tempcon" for electrical schematic.

http://www.evanstempcon.com/pdf/ccl/...schematics.pdf

You could recharge it yourself if the system uses "134a" refridgerant.
Home Depot and others sell the "AC Pro" recharge kit.
It all depends how handy you are with mechanical / electrical things.
Siggy

[DAJO]

Originally Posted by Roscott

Thanks Skip! If I'm low on refrigerant (I can check that, not sure why I didn't think of it), doesn't the compressor need to be running in order to fill?

The compressor will engage when refrigerant pressure is enough. You add to low side of system at the front of motorhome there should be a fitting for this. Most a/c experts (not me) don't recommend adding the refrigerant with additives, just the straight R134a. Don't add to much to the system, more is not better. To service properly gauges need to be used.

I am in the process of replacing compressor, flushing the system, adding the correct amount of oil and refrigerant. The only way to truly get the proper amount of oil and refrigerant is by weight and measurement of amounts added. Don't want to do over, going the extreme route first.

[DD788Snipe]

Make sure the low pressure switch is good and the connections are not corroded. It's a little switch that is screwed into the low pressure line with 2 wires connected to it. If you jump those 2 wires the compressor will kick in but don't do it for long. If your low in Freon it will damage the compressor. It will be in the front generator compart on the firewall. You can't miss it. Many times that can be the culprit. If not you may be low on Freon and in that case you have a leak in the system that needs to be addressed with dye in the Freon and a black light to find and fix it.

["007"]

Before you start apply a pair of vise grip pliers to one of the heater hoses to block off the hot water from getting into the Evans AC/Heating unit and see if cooling improves.
If it does your Evans control is installed incorrectly and you have three options change control and install correctly or install a ball valve as the thread you saw instructed.

[kustom]

watching this thanks

[Roscott]

Thanks Snipe, I'll try jumping the leads tomorrow when I get a chance. I thought I had an AC gauge from one of the car recharges, but not the case. Will buy one tomorrow to check freon level as well.

007, already did the vice grips test and will do it again if I ever get the compressor working properly.

All of this has been great information. Thank you all!

I'll post any updates as I continue to troubleshoot.

[DAJO]

Originally Posted by 007";3144241]Before you start apply a pair of vise grip pliers to one of the heater hoses to block off the hot water from getting into the Evans AC/Heating unit and see if cooling improves.
If it does your Evans control is installed incorrectly and you have three options change control and install correctly or install a ball valve as [B][URL="http://www.irv2.com/forums/f103/newmar-dash-air-for-2013-a-163596.html#post1592242

the thread [/URL][/B]you saw instructed.

None of this has any bearing if the compressor is not turning.

[Roscott]

OK, I went to the auto parts store and got a recharge kit with a gauge. When I connected it, it was over in the red. I got it back below spec and then gave it a 'boost' to get back into the green (area between the lines indicated on the gauge) but the clutch still did not engage. I checked voltage across the temp sensor and it was good. I also checked voltage on the valve in the first pic and it was good. However, it appears to be leaking as it has fresh oil all over it that wasn't there before I gave it a recharge boost. What is this valve? It appears to be on the high pressure side. Could it be causing the clutch not to engage? Can I replace it without evacuating the system? If so, how does it come off? Didn't seem too apparent as I was looking at it.

The second picture is of the entire system in case someone wants to point out what the heck I'm looking at or need to look at. Again, the pics are sideways for whatever reason. Thanks for all the help thus far.

One more question; could the control board that is supposed to be behind the dash panel be causing this? In the normal AC mode, the fan blows harder than when it is in the Max AC mode. I do know this should be the opposite. And I know the temp potentiometer dial should be good as I've used the heat function in the winter.

[siggyd]

On your low pressure switch in the top picture,you need to have 12 Volts on each terminal ,measured to chassis ground,when AC is ON. (Do not measure across the 2 terminals.)
Siggy

[Roscott]

Originally Posted by siggyd

On your low pressure switch in the top picture,you need to have 12 Volts on each terminal ,measured to chassis ground,when AC is ON. (Do not measure across the 2 terminals.)
Siggy

Sorry Siggy, poor wording. I did measure 12v from each terminal to ground, not across.

The lower valve (high pressure?) had 12v on the terminal on the left (coming from low pressure switch) and no reading from the other terminal (blue). This is also the one I believe to be leaking.

Also, about 30 minutes after my last post, I put the gauge back on...out of curiosity, and it went back to the red! I did not have the engine running when I did that.