QuestionThe problems started with the driver window. It always goes down, but sometimes won't go back up. The radio recently started acting up. The Front/Rear does the opposite as does the Left/Right, if it works at all. And more recently, the blower won't shut off. When you power off, the blower blows harder. The fan control does not work. The auto control regulates the temp but not the fan. Are these related problems? Do you have any suggestions?
Thanks
AnswerHi Hub,
I am a bit limited in responding to your questions because the latest diagrams that I have are for 1999 models of the T & C but then these areas of the electrical system don't change very much from year to year.
I don't see any common failure that would cause all these issues that you are having. While there is integration of many body electrical systems in the body computer module, the radio controls, the window motors functions, and the heater blower are not centrally mediated by that module.
The radio issue is probably in the radio itself. The door window problem would first be likely due to some corrosion or dirt in the control switch itself, so you might demount it and spray some electrical contact cleaner in the body of the control switch (or if that seems challenging you might just spray into the switch in the vicinity of the push button and hope that it fumes inside the body of the switch). Use a pressurized spray can of electrical contact cleaner with a straw applicator available from electronic supply stores.
On the blower, I am assuming that you don't have the digital type of automatic temperature control that complicates matters, but rather a conventional control unit.
Up to the late 90's the variable speed aspect of the blower motor was accomplished with a "resistor block" which is a voltage divider network that provides different voltages for the different blower speeds. The loss of control of the fan usually results from a failure of that block. But usually you can turn it off; it just only blows at high all the time when you have it on. So it may be a problem with the switch inside the control unit itself for the fan. You might have to remove the control, open it, and inspect the switch. Aside from thay unusual aspect of your situation, I would recommend that you look for the resistor block and inspect it. In the 90's that was to be found in the engine compartment, located in the far upper corner of the firewall on the passenger side of the car. It has a five wire plug and a couple of screws that hold in place with the electrical resistors hidden from view on the other side of the firewall; in fact they are in the air intake plenum that flows by that point that brings fresh air into the heater/ac unit in the cabin. The resistors are in that pathway to dissipate the electrical heat they generate in producing the variable voltages for the blower. So see if you can locate the block, unplug it, remove it and see if you find any sign of a burned out wire(s). You could plug it back in again and try to operate the fan at a reduced feed setting and see if any of the resistors get warm. If none do then that is a sign that something has burned out on the block. You can get one from a wreck at a pull-it-yourself yard if the dealer price for a new one is excessive. But that may not solve the problem of it being on all the time; that may be with the switch inside the control panel proper.
So unless the circuitry changed alot after '99 I don't think you will find a magic bullet that will fix all of your problems at once.
Let me know of your progress so that I learn from your experience.
Thanks,
Roland
