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2005 cummins wont charge ac

08-17-2011, 09:02 PM
have a 2005 4x4 cummings..
had to add some freon 3 weeks ago, then when out of town and left the truck parked for 2weeks. started it up and on the drive home the ac was only blowing cold(cool) air through the driver side vents and hot air on the passenger side.. thought the air mixer was sticking..
well next day nothing but hot air period..
put the gauges on and low pressue side was almost ZERO.. maybe 1-2 psi.. high side was about 140..
picked up some freon.. and it wont take a charge, maybe moved up to 5psi and get a little cooling on the line but no in the cab..
i have only the cheap gauges so i have to approximate psi but they are 134a guages. autozone guages not true refrigeration gauges that i can read with in a couple psi..

the compressor is engaging and have not found any blown fuses.. but will not take a charge, guages are not reading that have other issues..but what do I know..

is there a way to bypass the low switch or hi psi switch to suck up some freon.. ???

should i vacumn and recharge?
take to shop and hope for the best.... ouch..
any tech advise would really help.. only have the pdf for 2006, havent check only to see if 2005 dodoge cummins is valid

ok.. yes i propbably introduced some air into the system by not purging the lines.. but should not be so much to cause problems.. am i wrong

:headshake ok i am a dumbass.. the guage itself needs to be turned to charge the system.. but specs show 14 oz.. and almost through the can and still at best 20psi on low side and will post actuall pressures when i get done.

09-01-2011, 03:03 AM
Not sure if you're still having problems. If the compressor is engaging, then it should take freon from the low pressure side<edit> you should not have to(nor should you) 'jump' or bypass the low pressure switch if the compressor is engaging</edit>. If overcharged, the high-pressure cutoff will shut it down, and it will short cycle similar to low pressure cycling when under charged(but you will hear a distinct noise difference). You 'should' always purge your lines. A decent set of gauges is highly desirable, but not usually neccessary, unless you run into abnormalities. You may need to run a vacuum on the system to purge any air/moisture from the system, in which case you really want a nice set of gauges. Oh, and a vacuum/reclaimer. Harbor Freight sells a low-end $15 vacuum pump that runs off an air compressor. I have never used this, as I have a buddy who's HVAC with a nice reclaimer and a high end set of gauges. I imagine you would need a beefy air comressor to pull a full vacuum on the system, but this is a cheap way to ensure everything is sucked out of the system before the compressor is engaged.

09-08-2011, 05:49 PM
If it was my truck id just have it evaced and recharged by a dealer with a real machine (or even an independent shop if the cost is a huge issue) The reason it was blowing warm on one side and hot on the other is almost always because of a low charge issue (although it could be a blend door issue too sometimes). although with the readings you got it sounds like you may have a large leak somewhere on the low side. Anyway, just to be safe id have it checked with an actual a/c machine and hope you haven't damaged anything further because those filler cans tend to do more harm then good.

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