I purchased a 2002 Caravan Sport last fall. The heater works great and the climate controls worked fine throughout the fall and spring. In the summer I tried using the A/C and found that it wasn't blowing cold air (when tested in the fall it seemed to work fine but maybe it was just blowing cold outside air??).

When the A/C was on I noticed a distinct hissing sound that seemed to occur in waves (heard the sound then it went away then it came back etc - almost sounds like compressed air/gas is escaping then being pressurized again and escaping again). Now when I put the heat on, the same hissing sound is heard.

Any ideas/suggestions? Thanks in advance.

 

For anyone who may have this hissing sound problem or for anyone who was hoping to see an answer to the problem, I ended up taking my van to the dealership to have them look at it.

They immediately said it was low on refrigerant, without batting an eyelash. I booked an appointment for them to top it up and add a dye so that if a leak exists, they can use an ultra violet light to identify where the dye escaped.

The dealership said to drive around for a few weeks then come back so they can check for the leak. I'm keeping my fingers crossed that they don't find a leak and that the level was low simply through attrition.

By the way, the hissing sound also occurred when the AC was off but the defrost setting was selected. I asked about that also and was told that the defrost setting actually uses the AC system to remove humidity.