Rheem Furnace: ECM blower will not run – power and communication checks (code 68)

ECM blower will not run - power and communication checks (code 68) on a Rheem furnace: The communicating blower motor does not start on a heat, cool or fan call and the control shows 68.

Homeowner with a furnace problem? Call (647) 657-2977 or book a service call — licensed technicians across Vaughan and the GTA.

Applies to: (-)96VA040-115 (R96V / U96V) and (-)(-)96MDV040-115 two-stage variable-speed communicating furnaces

Common causes of ecm blower will not run - power and communication checks (code 68)

• No 115-120 VAC at the motor line connector
• Pins not seated in the 5-pin or control connector
• Control cable between P5 and the motor damaged
• Failed motor module

How to fix ecm blower will not run - power and communication checks (code 68): step by step

1. Unplug the 5-pin line voltage connector at the motor. With the door switch closed, check for 115-120 VAC between pins 4 and 5; line voltage should be there whenever the furnace is powered. No voltage: fix the wiring. Make sure every pin is fully seated, then plug it back in.
2. Unplug the motor control connector from P5 on the control and put 24 VAC on pins 3 and 4 of the motor side. With the door switch closed the motor should run at about 75%.
3. Motor runs in that test: the problem is the control or the control cable, not the motor.
4. Motor does not run: check the control cable end to end and pin seating; if the wiring is good, replace the motor.

If the unit shows an error code, look it up: Rheem Furnace codes

Models

96MDV040B30A96MDV060B30A96MDV070B30A96MDV085C50A96MDV100C50A96MDV115D50AR96VA0401317MSAR96VA0601317MSAR96VA0701317MSAR96VA0851521MSAR96VA1001521MSAR96VA1151524MSA