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 Chrys T & C.
MY front blower would only operate on one speed, no matter where i position the control to. Then, yesterday the front blower motor quit working. Nothing nada. The rear blower works fine and I know the air is cold when I drive it I can feel cold air from the vents.
Any and all help is appreciated.
Ron
Hi Sparky,
I believe I have found the culprit..Terminals 85 on both the front and rear blower relays are common to each other, as you implied. The two terminals are wired together via a trace on the PCB indside the fuse box, and run up to the connector for the front body control computer. This PCB is coated with some protective coating, and the solder joint where the FBC computer connector is soldered must have had some residual flux or something – as it appears to have corrroded the trace, subsequently burning it up. I’m assuming this all it was, and hoping that was the case – but until I am able to repair or replace the box I won’t know for sure…I appreciate your help with this so far, not the worst challenge I’ve had, but certainly the most interesting for some time. The fun part was taking the fuse box apart…
🙂
Bill
Hi Bill,
I did some checking and the only thing that would drop the front and rear blower out at the same time and not affect any other system is a faulty signal from the front body control computer. You will need to go to the underhood fuse box and check for power on fuses 10 and 12 with the key on. If no power is present, you will need to feel the front and rear blower relays, while someone else switches the ignition on and then off. No click, more than likely there is no switched ground signal from the front BCM to terminal 85 of either relay.
Hi Sparky,
Sorry to have left that info out, I have a 2003 chry T&C also. I had originally experienced the same issue as the other posts, where my fan would run constantly. this was about 6 months ago, and I was able to troubleshoot it down to the blower motor module, and changing that out with a new one solved that problem. Just recently out of the blue, while the van was running (we were parked) and the fan was blowing at high speed (was on auto hi setting I believe and cooling), it suddenly just stopped and has not worked since. I have checked all fueses, jiggled wires, tried bumping the motor housing, all to no avail. I tried the old failing module that originally failed just to see if the blower worked at all, and it still does not blow air. I measured about 1 or 2 ohms between what i think is the blower motor wire connections, and i also performed the voltage tests you describe above, but i don’t see 12v. I’m not sure where to go from here. I haven’t noticed any issues with the ignition switch that I am aware of.
-Rgds, Bill
It sounds kind of like an ignition switch failing. Does anything else not work? What is the year make and model of your vehicle?