ECM 2.3 Variable Speed Blower Motor Troubleshooting

By | September 7, 2016

ECM 2.3 Variable Speed Blower Motor Repair Replacement

ECM 2.3 Motors are used in HVAC systems frequently these days as blower motors.
This includes air conditioners, heat pumps, and furnaces. It can adjust the air flow depending on what the system is getting for feedback.
First of all there are two components to a ECM motor the control module and the motor itself.
ECM 2.3 Variable Speed Blower Motor Replacement
The motors by far fail the most but the control modules can also fail.
If the motor fails than it can simply be replaced. If the control module fails it needs the chip to be programed for the unit.
ECM modules have a common failure which is a thermistor which goes bad and is a common for these to fail.
ECM 2.3 Variable Speed Blower Motor Repair
Basics Steps to Locate the Problem with a ECM Motor
Caution must be taken when dealing with any HVAC system as there is high voltage in any system. Do not attempt to repair a unit yourself unless you have had training in proper high voltage pratices and safety.
1…Set the thermostat to Blower which should send 24 volts to G (blower) and C (Common). Be sure 24 volts is being supplied at the G (Blower) and C (Common) terminals.
2…Be sure there is high voltage 120 volts or 220 volts. Use a multi meter and verify the motor is getting power.
3…Power the unit off at the breaker. Separate the control module from the motor. Three wires which go into the motor should be tested for resistance one to the other.
ECM 2.3 Variable Speed Blower 111
This is checking the motor windings are good and each resistance value should be close to the other with-in 10 percent.
Also check each leg of the motor wires to the case to see if one has shorted out.
4…If the values are wrong than the motor is bad. If the values are correct and the motor spins good than the ECM is likley bad.
The above are simple steps to help narrow a down a problem on suspected bad ECM motor.
There are more test that can be done including with the right diagram for your motor jumping the harness to get the motor to run.
More than likley it will be a bad motor as this is the most common failure and it will need replaced.
ECM control modules do fail though so be sure to verify it has gone bad. Remember the control module is programed to work with that unit so it must go back on a new motor.
There is a common failure on ECM motors with the thermister going bad. Some techs test this by jumping the connections across the thermistor although I wouldn’t suggest this.
Control modules should be bought from the manufacture. Remember a 2.3 module from Rheem cannot be used on a 2.3 motor for a Trane system even if they look the same.
There are many problems that a ECM motor can have. Sometimes it is simply a pin on a molex connector the needs pushed in, other times the entire unit can be bad.


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