Chrysler Repair: No defrost? Cirrus, vacuum problem, hang ups

Question
I have a 97 Chrysler Cirrus Lx, ( I want to say 2.4.. it's a 4 cyl.)

I have a 5 position heater/defrost switch (round).  In the first 2 heat positions it appears to work correctly, but in the 3rd heat and both defrost positions, I get defrost from the sides (towards windows) but nothing from the dash.

I understand that it may be an electrical motor on my blower not opening a door, or that it may be a vacuum problem under the hood, but I don't know where to start or what I'm looking for to check.

Answer
Hi Jesse,
I have the shop manual but not the owner's manual so I don't know for sure what distribution pathways to expect from the 5 positions. I see the positions are labelled as panel, bi-level, floor (or 'heat'), mix, and defrost. There is a single electical 'mode' actuator for the panel/bi-level door and the floor/defrost door. There is also a blend door cable (which controls the temp), and a recirc door cable, and these are of course mechanical. The 5 position switch chooses different resistances to apply to a 5 volt reference line which produces different voltages that are sensed by the body computer which then operates the mode actuator in accordance. I can tell you the resistance values you should get between pins 5 and 8 of that 5 position switch, in the same order as listed above: 828-856, 1,278 to 1,315, 2,302 to 2,358, 5,202 to 5,319, and 99,500 to 100,500 ohms. So you could begin by checking those resistances, or by observing the motion of the actuator/levers in response to the different positions. The actuator drives several levers and I believe these are located on the driver's end of the unit so you may be able to look at that side from under the dash to see if you see any hang-ups. It could be the floor/defrost door is not being moved by the actuator, and is always staying in the floor position. There are no vacuum operated devices in this system.
Roland
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