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.
Did you overlook this part of the post? If you did read it what are your test results? You do have to have a voltmeter to test with. When you accidently grounded the heat sinks your were bypassing the internal circuitry.
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 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.
having the same problem, changed the power module and nothing..changed the blower and nothing. but accidentally bumped the heat sinks to the glove box frame and with a few sparks oh gosh the blower was working again, tried running a pigtail ground off the ground wire but nothing. only runs on high and cant shut of when heat sinks are grounded….next guess for me is the head unit…this is the automated heating/ ac…..so now what do you suggest…lol
Sparky, thank you for this info. I had the same symptoms that you described, and after replacing the blower control module (for $77), it now works fine. It took all of 5 minutes, too. You saved me the cost and hassle of taking it to the dealer. Thank you, thank you.
Tom
Towson, MD
The module costs about $90.00 and is a dealer only part. What temperature setting are you checking the blower speed control at and what is the outside temperature at the time of testing? Does the blower turn off when you turn the ignition off? Testing the module on your 2001 is the same as the 2003 I wrote about.
Sparky, what price range does this blower power module run? I’m not sure this is our problem, as our fan speed will fluctuate. We have a 2001 T&C limited with automated heating and AC controls. When we turn off the power (for the heating and AC), the fan continues to run and seems to run on high. Once the temperature warms to its setting, it doesn’t seem like the fan ever goes to low, but somewhere in the middle to high range. Someone mentioned that it may be a “temperature control sensor” but the dealership has never heard of such a part. Any additional thoughts?