Ram HVAC

Mike Owner/Technician Clifton, New Jersey Posted   Latest  
Question
Driveability
2013 Ram 2500 Tradesman 5.7L (2 EZF) 6-spd (66RFE)—3C6TR5HT1DG560598
No A/C

I'm looking for some help diagnosing an compressor no run situation on this vehicle. Customer is a friend that is a DIY guy and has done a bunch of stuff to this thing before giving up and bringing it to me. He has changed the compressor (new A/M) the pressure switch (new Mopar) and the BCM which is why it ended up with me to program the BCM. The only thing I've done is checked fuses and relay, also scanned the vehicle and found no codes in BCM (not even code to indicate it's not programmed). 

The symptoms are as follows, turn on A/C and the light on the control unit for the compressor will turn on but the compressor won't run (I've actually evacuated the system and charged with proper amount of freon). If you press the compressor switch the light will go out for a second then flash, if you press again it will light solid. At this point I'm looking for some direction. I would appreciate a wiring schematic for the HVAC system if someone could post one. This is not the type of repair I typically do, we are a collision shop. 

Thank You,

Mike

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Brian Owner/Technician
Springfield, Oregon
Brian Default
 

With a scan tool you will need to look at HVAC data, look for input from AC switch. Make sur pressure transducer shows same system pressure as your gauge does. Can you command AC on through your scan tool? Check the connection at the compressor. What was the reason for the compressor replacement?

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Ben Analyst
Warren, Michigan
Ben Default
 

I had the same issue with my 2010 Dodge Grand Caravan , the compressor doesn't spin, had to make sure there is enough Freon pressure, then with the help of my body and he is a certified automotive technician, he jumped the compressor using a tool through the connector wires. since then I got cool air coming through. not to forget check for any leakage. hopefully this with help you.

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David Mechanic
Stockport, United Kingdom
David Default
 

Hi Brian , scan all the vehicle systems and look for any issues that might lock out the air con . For example any temp sensors not reading correctly or the settings in the comfort control module .

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Mike Owner/Technician
Clifton, New Jersey
Mike Default
 

Pressure on scan tool reads 6.0 bar. When commanding with scan tool I get a compressor command "on", compressor engaged "false". Confirmed no power at at compressor. Not sure why the compressor was changed...I think he was just guessing at his problem

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Mike Owner/Technician
Clifton, New Jersey
Mike Default
 

Thanks for your help Brian. Your advice was spot on.

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Craig Mechanic
Huntsville, Alabama
Craig Default
 

Is fuse 62 in under hood fuse box hot on both sides with ac commanded on. The fuse is after the relay. If fuse is hot than you have a issue between fuse and compressor. if fuse is not hot check ac reley for power's and ground from pcm and see was its missing. Usually it's the tipm under the hood that causes this issue.

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Lonny Diagnostician
Largo, Florida
Lonny Default
 

Check for control signal at a/c clutch relay , if no signal received at relay suspect faulty pcm

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Mike Owner/Technician
Clifton, New Jersey
Mike Resolution
 

Found broken wires to compressor about 2 inch away from connector, possibly rubbing on steering shaft. Repaired wires, A/C compressor now works, thanks

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David Mechanic
Stockport, United Kingdom
David Default
 

Glad it’s sorted ! Bitter sweet for your mate though but that’s how we learn the best lessons or at least I do ....

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