A.C. Just Quit Blowing Cool Air! 2005 Cummins Dodge Ram

[eightballsidepocket]

Barely have any miles (19k) on my 05 long bed 4x2 CTD ram.

The wife and I was dropping off our new Travel Trailer at our storage place today, and then on the way out of the place, I pushed the little snowflake/AC button, and had the fan on, and the temp set on cold. I got just warm, outside air.

Normally you hear the A.C. clutch engage, but each time I pushed the snowflake button on, there was no clunk sound that I and all you folks are so used to hearing.

I checked the HVAC fuse/ok, AC clutch fuse/ok, and finally the AC clutch relay/ok. I swapped that relay with my wiper relay(both were the same model number/identical rated relays) that I knew was ok, and no cold air.

I swapped the wiper relay back to it's spot and the AC Clutch relay back to it's spot. Anyway, each time I pulled the relay and re-inserted it, and then hit the A.C. snowflake button, I'd hear a little click under the hood, and I'd get a momentary puff of cooler air, and then the air vents just put out warm, outside air as before.

What might be the problem? When I turn on the fan speed switch with the A.C. "on" there is no change in engine speed or "clunk" sound of the A.C. clutch engaging. Neither does the "clunk" sound happen or Clutch engagement when the fan is in one of it's speed positions, and I press the A.C. on/off button back and forth.

I'm still under warranty until August 2008. I will be calling my dealer's service folks Monday morning for a warranty visit.

Thought maybe one of you folks had a similar problem and I'd get advice on how to fix it myself if it was simple? It'd save me the warranty trip.

[JWC]

If it is low on freon, the compressor will not come on.  You can by-pass the low pressure switch, briefly, to see if the clutch engages.  If it does, either the switch is faulty or your system has a leak somewhere. 

If it is under warranty, I'd have it checked out.  Let them deal with it...as well as document that you have had an A/C problem.

[280Z Turbo]

That's Chrysler A/C systems for you. The compressor in my dad's Dakota has always been unreliable.

The only really good A/C system I've personally encountered has been the Hitachi system on my Z. After 30 years, the damn thing still blew cold! Almost makes me feel bad about removing it.

[S204STi]

Eightball, I replied to your post over at C/D about the issue.? I would add here that if you want to bypass the low pressure sensor like JWC was saying it is relatively easy to do.? Use a fused jumper to jump the terminals on the harness side of the connector (with it disconnected from the sensor) and then see if the A/C works.? If so, your sensor is bad.

Either way you're under warranty so I wouldn't worry about it.

[eightballsidepocket]

Eightball, I replied to your post over at C/D about the issue.? I would add here that if you want to bypass the low pressure sensor like JWC was saying it is relatively easy to do.? Use a fused jumper to jump the terminals on the harness side of the connector (with it disconnected from the sensor) and then see if the A/C works.? If so, your sensor is bad.

Either way you're under warranty so I wouldn't worry about it.

I'd take you up on the suggestion, but my compressor is located under everything and is more accessible from under the truck.  Seems to be this way on the Cummins engined Dodges. 

[TBR]

I really wouldn't worry about it at all, just let the dealer deal with it.

[SVT666]

If it is low on freon, the compressor will not come on.?

I'm pretty sure A/C systems have been freon free since the mid to late 90s have they not?

My A/C compressor makes a strange noise like an air compressor building up pressure and then it releases and starts all over.  The dealer replaced a part on it last year and it stopped.  It's making the noise again and the same dealer told me the noise is "normal".  I asked how it could be normal if it stopped making the noise last year when they replaced that part.  They had no answer, but comtinue to claim it is "normal".  It's a very loud and I only have 3000 kms left on my warranty.

[93JC]

I'm pretty sure A/C systems have been freon free since the mid to late 90s have they not?

Freon is a DuPont trade name for many different refrigerants. "Freon 12", ASHRAE (American Society of Heating, Refrigerating and Air-conditioning Engineers) refrigerant 12 ("R-12"), was banned in 1995.

New cars use R-134a, called "Suva 134a" by DuPont.

DuPont still makes Freon 22 and Freon 23, although Freon 22 (R-22), which is often used in residential and small-scale commercial air-conditioners, is being phased out in favour of R-410a.

[omicron]

Refrigerant nerd

[93JC]

I know these things from work.

[SVT666]

I know these things from work.

As do I.  I just didn't realize they still call them Freon since we refer to them as R-22 or R-410a.

[sparkplug]

You've got two windows. Use them.

[eightballsidepocket]

Call it refrigerant, freon, R134a.........whatever...............it all does/fills the same function.........Correct?

[AutobahnSHO]

Call it refrigerant, freon, R134a.........whatever...............it all does/fills the same function.........Correct?

Yes, just not as well-
It's more environmentally "friendly" but doesn't expand/ contract as much, which is what makes a/c work.

http://home.howstuffworks.com/ac1.htm

[eightballsidepocket]

Well, here's the results of the Dodge service visit today:

The system was a little low on 134A refrigerant, but they think that it's the "Pressure Transducer Switch", that's faulty or working part of the time.

The system seems to be leak-free otherwise.? Even though my refrigerant was down 1/2 lb. from full, the tech said that some units come from the factory without being fully loaded with the refrigerant.
*****
Anyone know exactly what the Pressure Transducer Switch does in the A.C. system?? I do know that it has something to do with turning on and off the A.C. clutch on the compressor or cycling the compressor.

[AutobahnSHO]

It tranduces.     











Hey, I got your thread to the top of the page, didn't I?? 

[S204STi]

That's the sensor I was babbling about.   It tells the system if it has too little freon, in which case it will shut off to protect itself.

[The Pirate]

It's going to be taken care of under warranty, right? 

[93JC]

As do I.? I just didn't realize they still call them Freon since we refer to them as R-22 or R-410a.

DuPont used it for a lot of refrigerants, and many people (older farts, I find) just call any refrigerant "Freon" (like calling a tissue 'Kleenex', know what I mean?).

I didn't even know about R-410a until I specced a Carrier split system with a matching fan coil and condensing unit using R-22. The contractor bought state-of-the-art units using R-410a ("Puron") instead. I wondered what the difference was and looked it up. Seemed okay to me, other than the extra cost to the client.

Didn't raise any flags until I realized the units they bought were half-a-ton bigger than I'd specced. 

[eightballsidepocket]

It's going to be taken care of under warranty, right??

Yes sir!

[etypeJohn]

I would schedule a visit to the dealer.  Let them handle it under warranty.  Until then use the 260 AC system the truck came with.

[eightballsidepocket]

I would schedule a visit to the dealer.? Let them handle it under warranty.? Until then use the 260 AC system the truck came with.

260 AC system the truck came with?????

In an earlier post I indicated that I had been at the dealer and a part is on order.  Until then, I wait for a phone call for the next appointment to install the arrived part.

[etypeJohn]

260 AC system the truck came with?????

Yup,? Roll down 2 windows and drive 60 MPH.? ?

[eightballsidepocket]

Yup,? Roll down 2 windows and drive 60 MPH.? ?