Hello NAMmers,

I'm just starting to try to figure out an A/C problem on a 2006 MCS with the automatic climate control. I don't drive that much, live in the North and I'm a windows open kind of guy and the A/C hadn't been turned on in ages, so I don't know how long it has been like this (years) but it did work well at one point probably 2 or 3 years ago.
It doesn't blow cold, or even cool. The light comes on when I push the button, set the temp in auto or hit the defrost button, but it doesn't seem to put any load on the engine.
My first move was to check the relay. I tested the compressor clutch coil resistance and found it to be about 5 ohms. Is that okay?
I found that when I jump the 30 terminal to the 87 I can hear the compressor click, but I don't know exactly what it is doing.
I also find that no matter what, I always get 14 volts to the 86 terminal of the relay socket. That can't be right. It doesn't matter if I have the A/C off, the temp set to max or even the system all the way off, always 14v there. Any ideas on that? I've been searching for hours but haven't found any references to this.
Help?

Thanks so much!

 

I would check the pressures on the compressor. Car is pushing 12 years and you said the system was not used for a couple of years. Would think the rubber o-rings have become dry and the freon may have leaked out.

 

Thanks for the reply WnW,

I did check the low pressure, and it is pretty much....well it's too low to read on my meter that starts at about 5. So I assume it's out. I have stuff to put in, but I thought it would be best to do a little checking first, and that's where I found what I think is an issue. I just didn't want to dump refrigerant in if there are other problems. If the 86 terminal is always hot, doesn't that mean the A/C is always on? Shouldn't the power to that terminal be controlled by the switch inside (or the auto system if in auto or defrost mode)?

 

I have a pretty similar issue that I haven't been able to find a fix for yet too. I re pressurized the system properly and nothing changed, but otherwise our symptoms are the same. Have you had any issues with the rear defroster or recirculate flaps?

 

I have since pressurized mine too--to no avail. My next move was going to be to replace the clutch coil on the compressor.
I haven't had any problems with the rear defroster. But I can't tell you about the recirculate flaps, as I don't think I've ever had it on re-circ. I'll have to check that.