Air Conditioning Compressor issues!

[BShuster]

Hi all,

I got a 2004. 5 RAM 2500 and the air conditioning quit working. I had it serviced this spring and the shop recharged the system and said there were no leaks or other issues. One day last week I noticed that the compressor wasn't coming on, in defrost or air condition modes. I'm an airplane mechanic and i'm looking for troubleshooting ideas and where to start. I know the compressor isn't kicking on, and the HVAC pressure should be good. What should I look for now? Thanks in advance.



Bob in Texas

 

[Simplysmn]

check for power at the AC clutch and go from there .

 

[MMeier]

Did you check for codes ? My '03 has a code for something related to A/C relay voltage high... or something like that. P0647 IIRC.

 

[Motorhead]

"the HVAC pressure should be good"... ... I wouldn't assume that just because the unit was charged recently it still has a sufficient charge. That would be the FIRST thing I would check.

 

[SierraRam]

You know what assume does right... ... . Anyway you need to gage up first to ensure you still have a charge in the system. The compressor will not cycle on if the low side pressure is to low. Once that is confirmed you can start looking at electrical/control issues. Since you added refrigerant they should have found and repaired the leak. If not it wouldn't surprise me that your original leak has become larger.



Good luck.

 

[BShuster]

There was never a leak in the system, earlier this summer it would not get real cold, so i had the dealership look at it. they told me everything was fine, during the checkout of the system they have to pull a vacume on it, then reservice it. It worked good after the reservicing. There is a chance they created a small leak while they were checking out the system and it leaked out enough to cause the compressor not to kick on due to low referigerant, but i really don't think that is the issue. I think it is a power issues or something else.

 

[MMeier]

Any codes ?

 

[TMax]

Sounds like the bad compressor clutch gremlin strikes again! First check pressures but if they are fine, check voltage to the clutch...

 

[RodMorris]

Since the compressor is on the bottom of the engine, I managed to mess up the connector driving through cornstalks. I cut out the electrical connector near the compressor and wired it straight through and haven't had a problem since.

 

[BShuster]

No codes, how do you check voltage to the clutch?

 

[Motorhead]

No codes, how do you check voltage to the clutch?

Pull the plug from the compressor clutch and use a volt meter across the two contacts on the plug. Must have the A/C on and engine running.

BE CAREFUL!!!!!

 

[BShuster]

Thanks Motorhead