AC quick cycles mainly when using remote start.

[Oil Stain]

This has been an on going issue since the truck was new. A 2012 3500 DRW Longhorn with 60k miles. After using my truck for a while shopping, I would use the remote start only to find the AC is blowing warm air. I can hear the compressor doing a quick cycle on/off. I've searched this forum and could not find anything. This was a big deal on the DodgeCummins forum a few years ago, countless people complained.

They said replacing the fan clutch solved the problem, sometimes. I have researched the fan clutch part number but it still shows it ends in a double "A", meaning first revision. Right? I believe it could be a sensor or a ECM issue. It doesn't do it all the time, but now it seems to be happening more often then not. Does Ram have an official fix for this?

 

[Dan_69GTX]

Does it happen w/o remote start - at all?

It sounds like a ECM, wiring, sensor problem, or many other things. Have you hooked up a scan tool to see what the ECM thinks the sensors are saying?

 

[Oil Stain]

I wish I had a scanner to read the sensors. It has done it a few times using the key to start, but more failures using remote. I only thing I can tell when this happens the condenser is super hot to the touch it will burn my fingers, when other times its just hot.

It seems to be a high pressure safety issue. If that condenser is that hot I would image that the pressures are very high and the quick cycling is due to the system protecting it's self. IDK

I would have to rev the engine to 2k rpm for as many 2 minutes while parked before it starts to cool normally or start to drive in 1st gear if in slow traffic as to try and cool down the condenser. The condenser is just a theory.

I would have thought by now a technician on this forum may have run across a TSB on the issue. The 2011-2012's seem to have been affected the most and during those years a lot of people have complained. Mine was livable at the time, now it's almost every time I do a remote start.

 

[RVTRKN]

Usually a sign of low charge. If it we're mine, I'd dump the charge to 1psi taking care to not release oil with the refrigerant. (slowly) Then charge the amount published on the sticker under the hood. But I do own all the nessesary tools and equipment to do it. However, it's the easiest and the most accurate way of making sure the correct charge is in it, before I'd start chasing ghosts.

 

[Kirwin]

Take it to an AC shop. They can diagnose it, usually for a nominal charge. Then you can decide to fix it ,or live with it.

 

[Dan_69GTX]

Yea, I agree to take it to a shop that KNOWS A/C systems. The hot condensor can be an indicator of high charge or not enough air flow. The fast cycling indicates a low charge - unless it is the high pressure cutoff switch. So, over or undercharge is possible with the symptoms. However, if it only does it on a remote start, that doesn't make sense if it is a charge issue. I've not done work in a newer RAM (under warranty, so why should I). If it is a expansion valve, what if the valve is sticking. Or, what if something is happening inside the system and crud is making it stick (compressor debris, dessicant bag breaking apart, etc). Or, what if someone worked on it and now there is moisture in the system, that would create an ice buildup at the expansion valve or orifice.

So.....It is something!

 

[sag2]

Do you have gauges to see what the pressures are when it's cycling?

 

[Oil Stain]

Do you have gauges to see what the pressures are when it's cycling?

Not anymore, but I can buy another set.