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.
Sparky, Thanks for you help, amd you not going to believe this. I had a hard time seeing the new part I got was bad so I rechecked the motor using the wiring on the 3pin connector to be sure the gnd and 12v were working. The blower cranked right up, but I noticed lights were now dim. I tried to start the van and it was dead. Would not even try to turn over. Disconnected battery and tested all the fuses with no luck. Next day after work, I charged the battery and the van started right up and the blower works perfect with new module in. Any explanation for something like this? Thanks again.
No, The new part that you just installed is no good.
Thanks again. I did more checking today and found that with the selector on rear control the fan stays on high regardless of setting. Is the blower speed control module the entire setup in the dash? The display and knobs everything? The dealer was pretty sure thats what I wanted. They needed vin, so I have to do that after work. Thanks
From your test results you have provided, the blower speed control module is faulty.
Sparky, I saw your reply after my other one. I went out again and measured -12V with black lead on blue and red on blk/org. That part seems ok. Now here’s where I am confused. Measuring between green and black on the 2 wire connector I first measured 1.8V, then after turning down the speed control it went to 0V and I could not duplicate that again. Now with my black probe on the metal bar in front of the connector for ground and using the red probe I measure 12V on each of the legs of the 2 pin connector. Measuring between them again results in 0V. What am I doing wrong? Also, I re-measured the blu/wht to about 2.5 V on high and 9V on low.