I have a 2002 Dodge Ram 1500 V6, And just yesterday i was driving with the AC on when i stoped at a red light and it started blowing warm But when i took off and drove for a second it was cold again well now Its doing it every time i stop.
I also noticed a "decrompessing" hiss sound when i shut the truck off?
I checked all Fuse's and there were fine.


Any help would be great

 

I would check the condensor. If the compressor stops at idle it is probably running hot and the safety switch shuts the compressor down. Clean those bugs out!

 

you might also take it to a shop that specializes in A/C work and have them check the system out. it could be you either have too much of a charge, which would kick the compressor off to keep from blowing seals. or you dont have enough of a charge. you cant build enough pressure.

but just as was stated above, check the condensor and make sure it isnt obstructed.

 

Classic description of a low charge, I'll bet you've got a leak somewhere!

 

Sounds to me like a low charge too.. Did you buy the truck new? If so, when was the last a/c service done? If it's been a couple of years, it's time to get the system checked and charged.. [sm=signs003.gif]

 

Hold the phones for a minute.. I was reading the July 2005 edition of Popular Mechanics and it's got an article about this in the Car Care section on page 115. The article is way too long to reprint and I don't want to get sued for copyright infringement but it sounds like you may want to have your Fan Clutch checked..

I'll see if I can find this article online and link to it..

 

my parents had that same problem with
their chrysler concord

-Jesse-

 

I'm going to expand a bit on what Tom said.

my little yoda, before I did alot under the hood it had the stock fan that was attached to the water pump pully. now while the fan would only engage from a mechanical sensor, it would still spin pulling air through the rad and condensorat idle. when the truck was moving the AC was nice and cold. when stopped it would warm up, but still be comfortable.

when I pulled that off and put in a dual electric fan setup I hooked the compressor sense wire up wrong and the fans did not engage when the compressor kicked on, which was creating ALOT of pressure inside the system, and the A/C wasnt cooling right. a few weekends ago I finly got back under the hood and got it hooked up right. it blows ice cubes now

you might need to check this, it could be that your not getting enough air flow over the condensor.

 

I would have to agree that the a/c systen is likely a bit low . It is normal for an a/c system to loose a bit of freon each year , it is not a true sealed system like a fridge or freezer.
This is an alowable loss of freon.

The hissing noise you hear is the systems preasure balancing out through the thermal expansion valve located at the firewall , this is normal.
Time for an evac , leak check and recharge if all ok.

Let us know what u find when you get it fixed.

 

Sounds like your condensor fan is inop. It is the small fan on the drivers side and should be running all the time while a/c is on. If fan is not running check fuse #39 in the power distribution center under hood. This is a common problem for these trucks and if problem is present the fan motor should be replaced and pcm flashed to prevent problem from reoccurring.