I swapped the belt on my 2004 2500 with a 5.7 the other day. Like an idiot I slipped and snapped off the transducer / pressure sensor plug on the A/C line.

The question is when I pull the sensor do I need the system evacuated? I assume I do. But was thinking that maybe there was a valve inside.

The dealer wants $90 for the sensor, then $120 to evacuate, change the sensor and refill the system.

I can get a sensor online for $70 but no one will install it if I buy it independently. Any ideas of how I can repair this without dropping $250 at a dealer? Probably not, but just figured I'd check.

Thanks

I would lower the pressure in the system by using the high pressure fitting. Wear gloves and don't breathe while your doing it or altleast turn your head. Take the sensor out and install the new one right away. No need to evacuate if it's done right away. That's for moisture..etc I'm pretty sure. Then go down to advance auto and buy yourself a recharge kit for $40. Easiest thing ever. Your letting r134a in the atmosphere. It's not Freon anymore. There are many other things out there that are far more pollutanous or however you wanna say it..lol

Interesting. So the fluid (R134) is not a gas? I just assumed that if you opened the system everything would shoot out and empty completely. However if I understand you right, I can simply let off the excess pressure via the shrader valve. Then swap the sensor quickly and just recharge the little bit that was left out.

bump for other opinions.


I ordered the sensor yesterday. Got it for $73 shipped online. Beats the heck out of the $94 the dealer wanted.

I think I'm just gona swap out the sensor... let the pressure out... then run it and see what happens. The only thing that sucks is I'm leaving for a trip this coming Thursday. Heading from here (Pennsylvania) to Harlan, KY towing my Jeep to go 4 wheeling. It's a 10 hour drive. Sure will stink without A/C

A lot of times when I've worked on chryslers the pressure switch is mounted to a valve so it wasn't required to evac and recharge the system.

Freon and r134a is a liquid. (pretty sure) Sorta like propane. it's a liquid gas if you will. Anyways, I'm no scientist but I do know Yes, it will expell out of the schrader valve as a gas. That is why I said turn your head and wear gloves. It's harmful to the atmosphere, but nothing like Freon is. It's illegal to let it open in the air, but that's B.S because think of all the people out there that have leaking A/C systems and just get them recharged every year. What about all that gas that leaked out. See my point?
The system is pressurized, but not by much. I am pretty sure you will need just about 2lbs to fill backup. There's a tag on the radiator support with the exact info you'll need.
Worse case is you take the sensor off w/out letting pressur down and the gas expells rapidly out of the hole. It goes very quick too. Count to 5mississippi and it's all gone. What they do is "purge" the system of all air so you'll get the coldest A/C possible. Same thing they do with new propane tanks so you can get more propane in there without the excess pressure. If you have air in there and try to put 2lbs of r134a, the pressure will be too much. There is a handymans way to do it, but i don't know. What I do know is I have had A/C leaks before and the Advance auto kits made them cold again. Never purged anything either.

Just unscrew it without removing any freon. It is screwed onto a schrader valve and will not leak when removed.

yeppers!

I went to a local salvage yard today and found a late 90's Ram with a 4.7L and it had a similar setup. So I pulled the sensor and saw the schrader valve. I went home and pulled the one on my 5.7 and sure enough it had a schrader behind it inside the little tube. That made my day. All I had to do was drop the $70 on the new sensor. Should be here Monday in time for my trip.

Glad to help

Freon is a copyrighted name for refrigerant owned by Dupont.

Refrigerant comes in many different types and they have different properties and operating pressures.
In the low pressure side of the system (suction) it is in a liquid state.After passing thru the compressor, it is pressurized into a high pressure gas. This travels to the condenser where it is cooled before going to either an expansion valve or orifice tube (depending on the system) where it changes to a low pressure liquid. It then passes the evaporator where it is cold and transfers cold to the air passing thru it. (Air going to the dash vents). It then is sucked back into the compressor and the cycle starts all over again.

So, yes it is a gas and a liquid. Just depends on which part of the system it is in while operating.