Intermittent Noise

I have an intermittent squealing that comes from behind the radio. The fan must be turned on and it does not matter if the AC is on or off. At 30 mph or when you turn the fan off the noise stops. I have replaced the fan, also the fan is located under the dash on the right hand, side away from the noise. As I said this an intermittent problem so it is hard to find. This problem is on a 2001 Dodge Durango with 150,000 miles.

Pat, Is It Possible To Describe The Squealing As "Whistling " ?
See If This Sounds Like The Condition:

" Some [2001 Only Durango & Dakota] vehicles may exhibit a whistling sound coming from the defroster outlets, low air flow at the floor in the floor mode or side glass fogging at low ambient temperatures when the blower is operated at higher speeds. "

" Operate the blower at M1, M2 and high speed with mode switch positioned in the
Floor mode, at the detent between Floor/Panel and Floor and at the dentent between
Floor/Defrost and Floor. If the whistling sound is present, perform the Repair
Procedure. If customers complain of the foot well being too warm after extended
driving or of the side glass fogging, perform the Repair Procedure. "

If that’s it then obtain a copy of 4 page Chrysler TSB (Technical Service Bulletin - written for Chrysler tecnicians) # 24-011-01 which outlines installing repair kit # 05080749AB in the HVAC system. At one time Chrysler did this repair while the vehicle was under warranty. It looks pretty involved as it paid technicians 1.5 hours labor and warranty often doesn’t pay as much as customers would.

A dealer can do this for you if the kit is available or a competent DIYer could give it a go.