No AC unable to charge with r134a

[bjgillisva]

I have a 2006 2500 and I've been having AC issues where it would work some times and blow ambient temp air other times then more frequently it would not blow cold air until now it just blows ambient temperature air. I've replaced the fan clutch and am trying to recharge the ac but the compressor will only kick on quickly 3 times before shutting off and wont let refrigerant charge the system. Is there a way to get the compressor to stay engaged? The AC pressure transducer does not seem able to be jumped like the old school switches on earlier trucks.

 

[Ozymandias]

Did you try to just let soak it in, slowly slowly to raise the pressure above the threshold value.

 

[Tuesdak]

What was in the system before you attempted to add R134a? AKA did you vacuum the system to charge by weight? (Just a touch under 2 LBS aka 32 OZ from memory on my 2003.)

However before wasting more R1234a on it: You have another problem, likely electrical, that isn't keeping the compressor clutch running. I would suspect a bad connector at the clutch coil or bad coil and possibly a worn (too large of a gap) slipping AC compressor clutch. The compressor could be locking up from internal damage.

A fan clutch failure (assumed as you didn't say) is hard on the AC system so guessing the compressor clutch burned up and/or compressor vented the refrigerant out the relief valve and then burned up.

A visual inspection of the compressor clutch is in order. Then probe the clutch connector looking for 12v. Possible the ground could be bad, but, you would see that if you probe both of the connectors with a voltmeter. One should be 12v and the other near zero with reference to a engine ground.

Did you try to just let soak it in, slowly slowly to raise the pressure above the threshold value.

That's a GM system with a low pressure cut out switch... Dodge doesn't care about pressure, only evap temp, and will run the compressor even with in a full vacuum pulled on it.

If the clutch isn't running at any time the AC light is on and fan more than "off" there is a electrical or mechanical problem that has nothing to do with the charge or lack of a refrigerant charge.

 

[B.G. Smith]

Not to disagree but there is still a clutch cycling switch on my 06. Compressor won't run with less than about 25# pressure. Are you using a set of gauges with adapters or one of those throw away kits? If you have gauges and cans, turn a can upside down and dump it or start dumping it then start the engine. No it won't harm the compressor. bg

 

[Tuesdak]

If there is a can connected to the AC system on the low side there should be at least 25 PSI in the system...

1st can going in upside down is a good point as small hole in the can and service port can't keep up with demand trying to take it in as a gas.

 

[bjgillisva]

I'm using manifold gauges and small cans of 134a. I ended up vacuuming the system out yesterday, added the requisite charge of 30oz, started engine, turned on AC, the clutch cycled on off 3 times shortly after turning AC on and stayed off. I then decided to pull battery cables and see if that would do anything. After pulling off all 4 cables and reattaching, started engine, turned on ac and the compressor engaged and cold air came out. Gauges read 31/225. Thought everything was good, came back this morning, started engine, turn on ac, nothing again, compressor cycled the 3 times and stayed off. Tried disconnecting batteries again, but ac still did not work when I went to restart after reconnecting batteries today.

 

[bjgillisva]

Ended up having to replace the compressor. Replaced with new Denso.

 

[Prairie Dog]

Ended up having to replace the compressor. Replaced with new Denso.

So everythings cool now?
(Sorry)

 

[PLohr]

Ended up having to replace the compressor. Replaced with new Denso.

I installed one of those Denso compressors on my 2003. From day one it was noisier than the OEM compressor but not enough to be concerned about ( it is a cheap compressor). Well, apparently that was a clue. It lasted 10-11 months then locked up. One year warranty and it looks like it is going to be replaced under warranty. But I put a new Sanden compressor on it, purchased right from Sanden. The Denso was about half the price of the Sanden.

This is speculation, but it seems that Denso is putting non-Denso parts in Denso boxes and selling them. Since when does Denso make knock-off Sanden compressors?