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.
According to the Standard Motor Products catalog that is the correct part number for your year model van with auto a/c controls.
Sparky, the auto ac in my 2003 Town and Country will not turn off (the fan). I turn the car on, the fan also turns on on full. I was looking to replace the resistor like you did above. But they are about $60 everywhere. I found another one for $43 RU399 HVAC Blower Motor Resistor.
However, I noticed that it only has 5 pins to plug in, as opposed to 6 pins on the oem one. But I also noticed that the van really only has 5 wires going into the resistor, so is the last pin not being used?
Sparky, thank you this was a simple repair and you were spot on. Part cost me $60 online and two minutes to replace. My wife was the most amazed exclaiming “you’re already done…I didn’t even hear you swear”.
Hi hitten1,
Other than the obvious checks on the wiring within the post, I would suggest looking to see if there is a blower relay in the system. I think there is and it could be sticking on.
Your testing indicates a faulty blower speed controller. You can check the blower motor by disconnecting the two wire harness connector and applying power and ground to the two wires. Those two wires attach to the blower motor itself. I try to refrain from bumping the blower motor until I have determined that both power and ground are present to the connector. The reason is because the blower motor could have brush contact issues that I will be affecting by bumping it. If both power and ground are known to be present, then bumping the motor is a good “proof” if it starts working. Bumping without having the proper signals present opens the door for a possible unknown issue with the blower motor itself. I hope this makes sense to you.