In this tutorial I'll explain how to test the blower motor resistor on the 2.7L V6 equipped Chrysler Sebring and 2.7L V6 Dodge Stratus.
Testing the blower motor resistor simply involves testing the resistance between terminals and making sure that there's continuity.
All the test steps are explained in detail and with your test results you'll able to find out if the blower motor resistor is defective or not.
Contents of this tutorial at a glance:
APPLIES TO: This tutorial and the blower motor resistor in the images I'm using in this tutorial applies to:
- 2001-2004 2.7L V6 Chrysler Sebring 4-door sedan and Sebring Convertible.
- 2001-2004 2.7L V6 Dodge Stratus 4-door sedan.
WIRING DIAGRAM: You can find the blower motor circuit diagram here: Blower Motor Circuit Diagram (2001-2004 2.7L Chrysler Sebring And Dodge Stratus).
NOTE: If you need to test the blower motor, see this tutorial: How To Test The Blower Motor (2001-2006 Chrysler Sebring And Dodge Stratus).
Blower Motor Resistor Basics
The blower motor resistor assembly is made up of 3 different resistors that are connected in series.
When current passes thru' them, the current is reduced. The less current the blower motor receives, the slower it turns.
To be a bit more specific:
- When the current is reduced by three resistors, the blower motor turns in LO speed.
- When the current is reduced by two resistors, the blower motor turns in Medium 1 (M1) speed.
- When the current is reduced by one resistor, the blower motor turns in Medium 2 (M2) speed.
- When the current is NOT reduced by any of the resistors, the blower motor turns in HI speed.
The resistors reduce the current flowing thru' them by converting it into heat. It's this heat that eventually will destroy the blower motor resistor assembly.
When the blower motor resistor block fails, you'll usually see one of the following symptoms:
- Blower motor works in high-speed only.
- Blower motor works in some speeds, but NOT all speeds.
It's very common for the resistor connector terminals to corrode or for the connector to burn and melt. This will make disconnecting the connector from the blower motor resistor block very difficult.
Another common problem is finding the resistor block coils corroded or burned out when removing the resistor block for testing.
TEST 1: Resistance Testing The Blower Motor Resistor
Testing the blower motor resistor simply involves testing the resistance between all of the 5 terminals and making sure that continuity exists.
To be a bit more specific, what we're looking for is to make sure that the resistance value between the terminals isn't in the thousand (K) Ohm range. Any resistance value in the K Ohms range and you can conclude that the blower motor resistor is defective.
If you're using a digital multimeter and you get an OL (Over Limit) resistance value then you can conclude that the blower motor resistor is defective and needs to be replaced.
NOTE: To see actual resistance specifications for the continuity test of this test section, go here: Blower Resistor Continuity Specification Tables.
OK, let's get started:
Disconnect the blower motor resistor from its connector and remove it from its location.
Visually inspect the blower motor resistor block and connector for burn damage and severe corrosion.
If the blower resistor block and connector have any heat damage (in other words: burns or are melted), you can stop here and conclude they're bad and need to be replaced.
Place your multimeter in Ohms mode.
Check for continuity across two terminals at a time. Continuity should be present between all terminals.
NOTE: If continuity DOES NOT exist between 2 terminals, your multimeter will display the letters OL (Open Loop).
Let's take a look at what your test results mean:
CASE 1: Continuity exists between all the blower motor resistor terminals. This is the correct and expected test result.
With these test results you can conclude that the blower motor resistor assembly is OK (not defective).
CASE 2: Continuity DOES NOT exist between some of the blower motor resistor terminals. This test result tells you that the blower motor resistor is defective and needs to be replaced.
If the blower motor resistor's electrical connector is melted or got damaged disconnecting it, you'll need to replace it too.
You can find my recommendations, on where to buy the blower motor resistor assembly, here: Where To Buy The Blower Motor Resistor.