My 2001 Grand Caravan had problems with the air conditioning. It started out where I couldn't get it cool enough. With both the passenger and drivers side set to the same cold temp, the driver side was not very cold, but the passenger side seemed to be working OK. Now there seems to be a noticeable hissing noise cycling under the dashboard. What could be the problem/solution?

 

Hissing noises are usually a vacuum leak.You'll have to get under the dash and look for disconnected or cracked hoses going to the heat-A/C control.It could be a fault in the control box itself.