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 copied this excerpt from the article.
“Blue/Light Blue wire should have a varying voltage from about 2 volts(high blower command) and a nominal 10 volts(low blower command).”
So yes, they do seem opposite normal human thinking but perfectly correct using electronics logic.
ok before i buy the chrysler module/resistor just want to check again. 2001 t and c lxi auto climate control,245000. blower went to high last month. boght resistor/module at oreillys auto parts. first one laster a week. second one lasted minutes.third time i bought new blower motor from advance auto[lower price] and exchanged module at oreillys{with a stern warning}.installes both worked at first then back to high.also put in a new cabin filter.ok read followup and borrowed multimeter.in 19 degree temp i checked wires,dark blue 10.9 striped blue between 1,2 and 6.9 as i moved fan control switch. waited and repeated after replacing batt in multimeter,i was warned it may need one. and results were slighty lower, guesing engine not running and cold temp to blame.the fan speed readings are oppisite of logical,ie high speed is the lower voltage. is thar correct?
The blower motor may be drawing too much amperage. There may be an airflow restriction that is causing the module to overheat. There may be damaged terminals that need to be replaced. Check the blower relay to insure that the module is receiving adequate voltage. Make sure the integrity of the module ground is good also. Possibly install an original equipment dealer part.
Have a friend with a 2001 T&C, has had a repair shop replace the module for the front heat/AC 3 times in last six months and keeps failing. Any suggestions to try next or what to tell the repair shop?