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 have a 2002 Town & Country with a bad power module. The van has auto climate control. The front fan ran at high speed all the time, regardless of speed settings.
I did all the tests above with a multimeter just to verify, everything pointed to a bad module. I purchased a new module and installed. The fan works correctly for a minute or less and quits. Powering off the climate control console seems to reset it, and the cycle repeats. The blower will operate for a minute or less, with the engine running. Ignition on, and engine off, the blower operates perfectly fine, can control fine. I’ve tried two different modules and get the same results. Ignition on scenario results in about 11.3V, while engine on results in about 13.5V to 14V to and from the module. It seems like the module does not like the higher voltage. I’ve run the fan with the module out of the duct for cooling, ignition on engine off and the sink has gotten warm to slightly hot to touch with no fan shutdown occurring. With engine running, the sink is not gettimg very warm at all yet the fan quits in a minute or less. Any ideas here?
Thanks for your help. Tested like you stated, then replaced the faulty module(app $83 w/ tax) and the fan works fine now. Very easy with your directions.
It could be the parts but I would suspect that the blower motor is drawing too much current and overloading the blower speed controller. It could be caused by a faulty blower motor or something blocking normal air flow. Dirty evporator core fins. restricted cabin air filter (not sure if you vehicle has one). Debris in the blower fan blade. You also could have a poor connection. Does the harness connector look okay?
Thanks for your quick feed back. But we just put in another resistor and it appears to working fine now. But this will be the third one in just a few weeks. Could I expect the problem to continue or did I just get two flukey parts. It is an automatic and it when it did blow it only blew on high speed no matter what the setting was and it blew harder when we turned the a/c power switch. We did the volt o meter test and all it well now. Thanks. I will keep in contact if it occurs again and we will go from there.
Could you clarify a few things? Manual or auto a/c controls? Did it only blow on the high speed setting or did it blow at high speed no matter where it was set? You said it blew harder when you turned the power off. A/c controls or ignition switch? Do you have a voltmeter or test light?