Chrysler Repair: Automatic temp control blower motor stuck on high, fan blower, car manuals

Question
We have a 2001 Chysler Town and Country 3.8 V6. It has 3 zone auto temp control. The blower will not shut off with the power switch. In fact when I shut off the power to the blower it blows even faster. The only way to slow it down is to turn on the AC. I still have no real control, the fan is just a bit slower. I followed directions on your site and visually checked the resistor block in the air duct. The circuitry looked intact and I did not detect any burnt smell. What do you think, is it the main on/off switch, the fan speed switch or the blower itself. I didn't try pulling the fuse, but I think that would shut off the blower.

Answer
Hi Mike,
I don't have a manual for your year of van, only older car manuals with the ATC type unit. I am not even clear as to whether there is an old-fashioned resistor block(with simple resistors) or a module with some transistors (as in the car ATC units).  If the unit just has the resistors and the thermal limiter and is a 4 speed fan, then I would try checking the continuity of each of the resistors and the thermal limiter (which is a temperature controlled fuse, basically) in that block. If they all show conductivity then I would suspect the switch. If the thermal limiter is 'open' (which could happen without and noticeable smell) then you need to get a new (or used) resistor block to get the multispeed function back. If on the other hand, you have the many-speed motor and the transistorized module, I would check the light green/red wire coming to the module, when you have the fan blower running and various speed settings selected and read the voltage on that wire to see if it varies depending upon the speed selected. If it doesn't then the switch would be suspect, if it does vary, then the module is probably bad and needs replacement. Just insert a pin thru the insulation and measure the voltage between the pin and a shiney body structural metal surface (ground).
I wish I could be more specific, but I lack for wiring diagrams.
Roland