2003 Dodge Grand Caravan - heater fan only works full blast
 

We have 2003 Dodge Grand Caravan. Recently the heater fan only turns on when it's at full blast. Any lower settings the fan doesn't engage. There seems to be some heat but no fan. Any ideas why this is happening? Thanks!

Very common. The blower motor resistor is burned out. The part is about $25 and you can replace it yourself. Do a search for blower motor resistor and you'll get plenty of hits.

3 zone will cost 75 bucks and is behind the glove compartment..2 screws and 2 wire disconnects and your done.

I have the same issue. I went to the auto wreckers today and swapped out the resistor and still the fan only ran on high. I tried 2 different resistors. Could it actually be the fan motor? Didn't think it would be since fan runs on high.

Thoughts?

You should actually replace both the resistor and the fan motor. excessive current draw in the motor is what causes the resistors to fail. When your blower motor is bad enough, it will blow a new resistor instantly.

My brothers 2002 Stratus R/T 4-dr resistor block failed (high fan speed only) under warranty and the dealer only changed the resistor block. That was 7 years ago and he's never had a HVAC issue since.

My dad's 2004 Stratus base model had the same falilure mode (high fan speed only). I replaced it and he's had no problems since.

You would expect if the blower motor was at fault (high current draw) the fuse should blow and the blower totally quit.

The high speed blower speed electrical path does not need to pass through any of the resistor block channels to reduce the current to the motor to obtain the slower speeds.

Stratus is totally different from a caravan. They used a credit card type resistor in them and the design totally sucked. They would overheat and fail so all they needed was a resistor. The new resistor has been redesigned and is more like a conventional resistor now.

You may have found two other bad resistiors. Do you have access to a multimeter (digital or analog)? What you should do (and what I did do on my dad's Stratus) was to verify the OEM resitor block was faulty. One leg should have minimal resistance (that's High Speed) and the other curcuits will have infinite resitance (an open Circuit), thus why no speed other than full speed works. If the resistor block is good, you should have four different resistor values - one for each speed of a 4 speed blower motor.

The basic trouble shooting process is the same for all applications unless you physically can't get to the different resistor circuits - say if was ECM/PCM/BCM software controlled.

Whether it is a Stratus or a Caravan, the basic trouble shooting process is the same.

Get a multimeter (digital or analog) and check the resisitor block. The two junk yard resisitors may have died too.

A good block should have four different resistance values- one for each speed. If you check the two junk yards (plus your original) you'll most likely find only one circuit of each resistor block is open (infinite resisitance) - the high speed fan.

If the fan motor itself is bad (bearings going, brushes, etc.) the fuse should have blown.

not that this is a caravan but had same issue with my 03 dakota dealer replaced resistor.. no problems since .. 2 yrs and running