Hi, we have a 2002 2.7 L Intrepid with 139,000 miles. It's been fairly trouble-free for the most part, until last week when we noticed the heater and A/C wasn't working, as in no warm air, no fan, and no A/C at the fan setting we normally use. Here's the wierd part: if we turn the fan to the highest setting everything works fine! But turn it down a notch and the fan stops and the A/C light goes off, and no warm air comes out of the vents. We're pretty sure it stopped mid-commute three days ago.

Now, this is a sort-of workable condition, since we can turn the fan on to blast off a foggy window or warm up the car, but it's noisy and frankly just too warm to leave it on for long. We hope to keep the car a year or so longer. Any suggestions? My husband has looked under the dash and consulted the manuals, but he thinks he'd have to take the dash apart to diagnose further.

 

It sounds as if your blower motor resistor is burnt out.

The resistor is what gives you multiple blower speeds. They fail from time to time on their own, other times they fail because the blower motor is drawing too many amps due to being old and the resistor burns open like a fuse.

The reason high speed works is because high speed doesn't use the resistor. Everything else stops because when the blower quits, the system thinks you've shut it off.

The resistor assembly is mounted in the bottom of the blower plenum. It should be facing the floor, in the plenum behind the glove box. I don't believe you would have to dissassemble the dash. Maybe glove box, but that should be it. To locate it, follow the heavy wires from the blower motor to the resistor, one is black, the other, I think, is green??

The other possibility is the blower switch, but I would check it last. The resistor failure is much more common. If the switch is bad, I believe it is an integral part of the control panel and the whole thing would have to be changed.

Hope it helps.

007.