It's fun reviving old threads lol. And oh my goodness as an HVAC technician seeing a lot of the misinformation presented from years ago by people made my want to pull me hair out!

 

How about setting the record straight then?

 

I have 03 Dodge Ram 5.7
hooked up manifold and reading were on the low side
20 and 120
and clutch was cycling on and off.

got refrigerant hooked up to yellow line but never opened low side.
readings went through the roof and compressor clutch would not disengage.

exchanged relays
checked fuses
no luck
only way to get clutch to disengage is to pull relay or shut truck off.
high side got to 350 without clutch disengaging so I **** it down.


only thing I can think is pressure switch just happen to go in that time from checking pressure to hooking up refrigerant to manifold.

 

houses are 24v
Everybody needs to stop saying “Freon”
there should never be ice on an evaporator unless you have a problem.
There are other things I question as well about the car systems but I’m not confident enough in my opinion to call anybody out.

Not really that much stuff actually now that I reread the whole thread again.
and just to clarify I am a house and building hvac technician, buildings and cars have several differences. The basic principles are the same but with issues like the original poster from 9 years ago had my knowledge doesn’t go too far.

 

yes "Freon" is an outdated term, but it has come be used as a catch all term for refrigerant . . . . its kinda like calling a tissue a kleenex . . . . wrong, but everyone knows what you mean.

 

I know it's been a while since this thread was started, but I have a similar issue with my 2007 dodge ram 1500 5.7. I have replaced the condencer, evaporator, dryer, and ac compressor twice now. The compressor seems to be constantly running even with the ac off. The only way I can get the clutch to disengage is if I pull the plug. Any suggestions?

 

Does the compressor run, even with the climate controlled turned completely off?

 

yes, with everything completely off she still engages. When I unplug it I can turn the pully and clutch separately so I know its not locked up yet.

 

Hhhmmm..... I don't know how the clutch on yours is wired..... Pretty sure it is controlled by the PCM though..... Likely a relay in the TIPM for it..... wonder if the control wire for that relay is grounding out somewhere, or the relay has just gone bad.

 

So I had the TIPM rebuilt shortly before I noticed this problem, I brought it back to the shop and they confirmed the TIPM is the problem, however, they cannot get a hold of the company that rebuilt it in order to fix it. In the mean time, someone suggested that I run a toggle switch to the compressor so I can turn it on and off manually. is that a good idea or am I still going to blow my compressor if I let it run too much?