2003 Chrysler Town and Country Van came in with the complaint of the blower operates on high speed with key on and cannot be adjusted down. This procedure will also apply to Dodge Caravans with auto a/c. The controls and indicators seemed to work normally. I checked the wiring diagram and component locator and found that the blower power module is located behind the glove box. Good place to start.
After opening the glove box there are two stops the have to be depressed inward in order to drop the box down.
The blower power module is directly behind the lowered glove box. It is held in place by two 8mm hex head screws.
After removing the two attaching screws, the blower power module can be positioned for testing.
Turn the key on and while manually rotating the blower switch from low to high you should see a voltage change between about 2 volts (high)up to about 10 volts (low) on the blue/light blue wire. It is the middle wire in the left connector pictured below. Because the blower was working on high speed there was no need to do any other testing, however if you were to have low blower or no blower you would need to test further. Check for 12 volts – on the black/orange wire and 12 volts+ on the dark blue wire in the three wire connector. If either is missing check respective fuse and ground connections. Next check for 12 volts between the blue wire and the dark blue /yellow (sometimes black as pictured below) wire in the two wire connector to the right of the pictures. If either signal is missing in the two wire connector and the three wire connector tested good then the power module is faulty. If 12 volts power and ground are present then the blower motor is faulty. Usually bumping the motor with the key on and the blower switch on high will make the motor work for a little while because it will reset the worn brushes.
Three wire connector:
Black/Orange wire should have a constant ground.
Dark Blue wire should have 12 volt switched power from the front blower relay. The front blower relay is located in the Integrated Power Module (underhood fuse box).
Blue/Light Blue wire should have a varying voltage from about 2 volts(high blower command) and a nominal 10 volts(low blower command).
Two wire connector:
Check for a nominal battery voltage reading across the two wires. Key on and blower set to high.
I removed the mounting screws to gain better access to the wiring for testing.
Be careful to keep the aluminum cooling fins away from the metal brace for the glove box. It will complete the ground circuit for the blower motor and will scare you when it sparks.
Place an insulating cloth between the aluminum fins and the brace if you want.
A good look at the blower power module.
Installed the new blower power module and all is well.
I would agree that the blower speed controller (what you refer to as a resistor) is faulty.
Sparky,
I have read all your posts and am going to try testing the voltage. Just to get your opinion my 03 TC with auto climate control fan works just fine on high speed but when changed to a lower speed the fan will quit about 30 seconds after changing it. That being said if you turn power off to te unit then turn back on it will immediately start back up but shut off again unless moved to high speed. I changed blower resistor and it worked fine for a day or two then started acting up again. Any suggestions??
Thanks, Jake
Thanks for all your help Sparky! I have confused myself reading through all the comments so I thought I would tell you what my readings were to find out if my resister was showing bad.
Three wire connector
12 volts on dark blue wire.
range from 2 to 12 volts on middle blue/light blue wire
I checked the ground with the ground connection on the orange/black wire and the positive connector on the dark blue. reading was 12 volts.
2 wire connector had 12 volts on both wires when connecting to ground. I had nothing when connecting the two together.
This lead me to believe my resistor was bad. I hookecd the wires coming from the blower motor directly to the battery and the blower motor was working.
Do you agree with me that my resistor is bad?
My town and country is a 2003 with automatic climate control.
Thank you.
Bryan in Fort Payne, Alabamas
It sounds as if you have a missing ground control circuit for terminal 85. Terminals 30 and 86 have power at all times from the same source. you stated that you can jump between 30 and 87 and the blower works. Can you feel the relay click when some one else turns the ignition and HVAC controls on?
I have 2003 T&C limited. I have not front or rear blower control. I am getting no power at the 3 pin connector behind the glove box from the relay. The relay and fuses are good. Is there another component other than the fuse between the relay pin 87 and the module behind the glove box? I have ATC and have replaced the electronic control in the center console as well – no luck. I am stumped. I did try shorting pin 30 to 87 on the relay and things worked fine.