It could also be part of the A/C. I forget what it's called but it's the
valve block that releases the highside pressure to the low side pressure.
Whenever the A/C is on, it is in operation and may be audible. With most
Chrysler products, the A/ is on whenever the defroster is selected, so
you'll pressurize the system and could hear the noise.

This might make more sense because your rear A/C unit is located in the
passenger side, rear corner. It even explains why you hear the noise after
the ignition is turned off. (Listen closely near the glove compartment and
you'll hear the same noise.)

As long as the A/C compressor is cycling normally, there probably no leak in
the system and nothing to worry about.

Hope this helps.

Bob

"Bob Snyder" > wrote in message
...
> Fuel pump? It will sound like a gas leak.
>
> "qdn" > wrote in message
> oups.com...
>> 2000 Town & Country Minivan - Hissing noise coming from the back on
>> passenger side.
>>
>> Before I get under the van to do a detail inspection, I though a quick
>> question may help.
>>
>> While driving, it continously hissing on and off as if the air is
>> deflating from somewhere...
>>
>> Thks
>> qdn
>>
>
>