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 would check the circuits at the blower motor as well. The brushes could be nearly worn out and giving the same symptoms. Power and ground present at the motor wiring when the inop condition is present. Bump the motor to reseat the brushes and see if it comes back on.
r aSparky,
First, I want to thank you for what you are doing to help all of us shade tree mechanics. Lord knows I need all the help I can get!!!
Anyway, I have read most of the previous comments but did not find one quite like my problem. I have a 2001 T&C Limited with Auto Air. The back blower works just fine. The front blower will come on and run fine, sometimes for several hours (like on a highway trip) but other times (could be as little as 30 sec. The blower will start slowing down and finally quit. Sometimes if I turn the blower switch all the way down and then back up the blower will start again. Every time is shuts down this way I can power it off and right back on and the blower starts up like normal. It may keep going for awhile or slow down and stop in a matter of several seconds.
I replaced the resistor and everything seemed OK for a month or so then it all started again.
Since the temperature down here has been 100+ I have not worked on it lately but there is a promise of cooler weather next week so I thought I might be able to try your recommendations then.
I know the resistor is the most likely problem but before I drop another $80 I thought I would ask.
Again, thanks for all your help.
Jim
Texas
That would be correct.
Sparky first and foremost, thank you for your help. I have a 2002 T&C LXI. If I’m understanding correctly if the fan is stuck on high, and you have variable voltage on the lt blue/blue wire . It’s the module that is bad. Mine is ~1.9-8.
Thanks again, Brian
Hi Jake,
I would need to see some voltage test data to provide good feedback. One simple thing that you may want to try is to give the blower motor a firm bump with the heel of your hand when it is acting up. If it cleared up after a bump, the motor is likely to be faulty/failing.