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.
Hi Sparky great site!!
I have to same fan on high constantly problem. Town & Country van 2002 with auto climate control.
I followed the voltage check instructions and got:
blue/lt blue low 6.7 high 1.6
black/orange 95 Mv
2wire conn. between wires 8.5
dk blue to grd 10.25
battery 11.5 + to –
Put in a new resistor block with no change in the constant fan issue.
I then checked the new resistor against the old resistor with the ohm meter function and found readings between similar terminals getting similar readings. How likely is the new block bad out of the box?
Thanks
George
The control head could have an issue but that would show up in your testing. You probably got a faulty replacement part or more likely the blower motor is drawing excessive current and has damaged the replacement part. I am assuming you have auto a/c controls. You stated you changed the “resistor” which is for a manual system but you mentioned a cost of $75 which is inline with the price of a blower speed controller.
I have a 2002 Chrysler T&C. I replaced the resiter ($75 + tax) and it worked for one day. Now it is back to running constant on high, although you do get heat. What else could be wrong?
From Pat in Wisconsin
You are right, on the 2 pin connector it should read the probes on the green and black wires = 8.8v.
I doubled checked my notes and that 0.11v on the black/orange and dark blue wires was with the key on. The battery was running pretty low at the time if that matters.
I was hoping to not have to try to get that fan off but I guess I have no choice.
Thanks again Sparky for all your help.
Your voltage reading is off when checked between the dark blue wire and the black/orange wire. It may have been a typo or you may not have had the key on. Also your last voltage reading of 8.8 volts did you mean to state that was between the black and green wires at the blower motor connection? From your general description and my inference of your data, a new blower motor and possibly a new blower speed controller will be needed to repair your system.