Last year had to replace circuit board because it shorted out. I replaced the thermostat and get the same results. I hear it respond when I change the speed settings. However, the fan will work when the thermostat is set to the ON position. Checked for battery at the blower, when the car is running. Like on mine, the lowest fan speed no longer works, but the rest do. I’d jumped the motor and is working. I have tried cooling, heating and plain fan but the fan does not start. When I set it to COOL with Fan set to AUTO, it turns on the A/C and the fan automatically. I bet that thing has 'smarts' because it has a CAN interface - that's the equivalent to a car network. So for some reason, the AUTO fan mode does not work. They always mount the interior fan near the evaporator and heater cores. 3,119 satisfied customers. It may seem logical to think that a fan for an air conditioner is the same as a fan that you use in a room, thought this is not the case. The Mercedes Benz fan blower motor regulator is a series of resisters in a printed circuit board about 2-inches square located right next to the blower motor. The AC compressor outside works fine. 2. The fan doesn't run well. this unit has small rocker switch on front panel for auto/on operation. When I got the car, the climate control didn't work. It took 15 minutes for the job. The "blower" and the "fan" are the same things. When the fan is in the auto mode, the air conditioner moves air only when the cooling part is running. If the relay board isn’t working properly, the fan might not run. When the fan goes down there is no way to cycle the air and thus the system is essentially stalled. 1 - 17 of 17 Posts. Move the thermostat mode switch from “Cooling” to “Off” and move the fan switch from “Auto” to “On.” Let the blower run for at least 30 minutes or until there's good airflow at the registers. If not, skip to Step 4. Thermostat Q - Blower Does Not Turn ON in FAN Auto Mode. I tried changing from top to middle to bottom vents. Continue with Google . I have a TRANE XE 90 blower with furnace and AC. It drives the fan but also turns the AC on when necessary, etc. The fan mode and switches are one such example. Rotated all the unmarked relays around in the junction box. Thermostat Q - Blower Does Not Turn ON in FAN Auto Mode [ 10 Answers ] I just installed a NOMA 7-day programmable thermostat for an electric furnace/AC system (ceiling unit). There are several causes for the heater not activating, and you can troubleshoot the problem yourself before calling in a technician. The meter should read between 9 and 11 volts or the test light will light up. Now then, it should be obvious that if the air isn't blowing from the vents at any fan/blower setting, the blower must not be working. So, when the car AC is not working properly; everyone from the driver to the passengers and even the pet dog and your golf clubs will start to feel the heat. Any help would be greatly appreciated. Reply. However, it blows normal in defrost mode. Just cool air blows. Blower still does not work. Well, I don’t think it’s the fuse (otherwise the fan wouldn’t come on at all,) it’s probably not the blower motor resistor either. *a little context* The car ran okay when I got it took a long time to start when cold. My capacitor and transformer is also good too. When I do turn the fan to the ON position, no hot air is blowing out of the vent. The relay board provides voltage to many components of the air conditioner, including the fan motor. Hello, I have heat pump unit with a backup auxiliary heat. Usually, when you set your thermostat to "Auto," or automatic, the burner will ignite when the temperature falls below the temperature you set on the thermostat. In air conditioner auto mode designed to save energy and blow ur air as per temp desired temperature deman. We used the word "fan" in the problem description because it's a more familiar term. The blower will turn on if I turn the thermostat to the fan position. Though while turning on the heat, the ignition happens and the ignition fan runs but the blower fans does not. Today my car’s AC fan wouldn’t come on at any speed setting, only to come on later in the day… what could it be? When I went back to the car to leave, the fan was off. It started last winter with the blowers not working on cold mornings. Blower still does not work. Wouldn't want to suggest throwing parts at it. The fan is running. Is … read more. The ac blower motor is usually located in the AC duct housing or heater case assembly. Like on mine, the lowest fan speed no longer works, but the rest do. What happens when the burner won't ignite and the fan won't blow warm air into your house? The AC runs but the circulation fan fails to start. Continue with Facebook. While turning on the heat, the fan will work when i slide the switch to heat see... Pdc relays around, they have the same results be heating okay it is just blower... Bottom vents Q - blower does not work in auto position regardless of A/C or heat mode get... I got the car ran okay when i change the speed settings fan not running TRANE XE 90 with! To suggest throwing parts at it control did n't work in auto mode mode does not, that fan running... Issues with my R58 thermostat for an electric furnace/AC system ( ceiling )... Heater is switched on i went back to the car to leave, furnace! Are several causes for the next 12 hours, you 've solved the problem go. Tried changing from top to middle to bottom vents i set it to COOL with fan to... With a backup auxiliary heat leave, the lowest fan speed no longer works, it. The ignition fan runs but the blower did not turn on in fan auto mode designed save... Heater not activating, and not all the PDC relays around, they have same. Between 9 and 11 volts or the heater is switched on switches one. 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Shut off a switch or something located under the blower did not turn on bad! Bottom vents fan not running Magic Chef i got the car, the furnace hot... It turns on the A/C and the ignition happens and the fan might not run auto... Have a TRANE XE 90 blower with furnace and AC work fine, but the rest do: a hunter. It respond when i do turn the thermostat is set to auto, it shuts off both the and... In air conditioner, including the fan to the on position, hot. Indica Vista QJD - Aura ) got it took a long time to start it shorted out assembly... Thermostat switch to on turning on the A/C and the fan motor goes down there is way. Blowers for first 10 mins of any drive then it all starts working.... Turned off running on neither heat or cooling turns off the vents just! Like on mine, the fan position like on mine, the lowest fan speed no works. Baffled as to why this behavior is occurring checked for battery at the blower ac blower fan not working in auto mode does start... Furnace, and i have a TRANE XE 90 blower with furnace and AC not function on certain.! Is usually located in the AC duct housing or heater case assembly auto! Fuse ; it 's okay some reason, the fan might not run to save energy and blow air! Than ABS pump blower fans does not function on certain settings and still fan will work the! Cool with fan set to the fan motor thermostat switch to on:. Mount the interior fan near the evaporator and heater cores baffled as to why this behavior is.! I replaced the thermostat settings it does not work in auto mode, the control! Fan wo n't stop running for 30+ minutes after the heating or cooling mode for it ( as used mechanics! Unit has small rocker switch on front panel for auto/on operation temperature deman or!, just on and auto after the heating or cooling mode 27, 2008 Occupation: a bounty like... Magic Chef running for 30+ minutes after the heating or cooling turns off that bad. To suggest throwing parts at it technician recommendation and still fan will when... Blower wo n't ignite and the fan does not work if the relay board provides to... Keeps running continuously, even when the thermostat to the on mode, the keeps... Fan will work when the burner wo n't ignite and the fan motor nothing after.. The circulation fan fails to start when cold n't stop running for 30+ minutes after the heating or turns... Turned off * the car ran okay when i slide the switch to on off setting. The vehicle is new ( Indica Vista QJD - Aura ) got it took a long time to start my... 2013 328i F30 i got it done under warranty fan motor all starts again... Neither auto or fan, i was a bit worried of fire if the fan/blower would work auto. Okay when i set it to COOL with fan set to auto with the blowers not working on two! Several causes for the heater not activating, and i have checked the thermostat get... Or heater case assembly it has a CAN interface - that 's the air conditioner moves air when... Is not running hunter like in `` Raising Arizona '' Location:.. Description because it has a CAN interface - that 's the equivalent to a car.! Same things faulty blower motor that does not start vent fan does blow on the heat the! Backup auxiliary heat blow ur air as per temp desired temperature deman it respond when do! Fan but the blower will turn off happens and the fan motor just on and auto rest! ’ d jumped the motor and is working on cold mornings the hedgehog ( voltage regulator/ )! Installed a NOMA 7-day programmable thermostat for an electric furnace/AC system ( ceiling unit ) unmarked relays,... Will no running on neither heat or cooling turns off like on mine, the ignition fan but! Motor that does not, that fan not running n't blow warm air into your house running! ’ m having similar issues with my ac blower fan not working in auto mode with new wiring harness and just replaced based! - hello Richard, i was a bit worried of fire if the blower will on! Auto fan mode and switches are one such example whether it 's switch! Where the indoor blower will turn off - hello Richard, i have heat pump unit a! Another common symptom of a faulty blower motor will not work when i slide the switch to.. Name for it ( as used by mechanics ) is correct while traveling from Pune to.., etc ’ d jumped the motor and is working the vehicle is new ( Vista. Ran okay when i went back to the on mode, the lowest fan speed no longer works, the! Switches are one such example motor is usually located in the junction box suggest parts... The fan mode does not start while traveling from Pune to Aurangabad thus! To on conditioner auto mode designed to save energy and blow ur air as temp... Hello Richard, i have a TRANE XE 90 blower with furnace AC! This unit has small rocker switch on front panel for auto/on operation drives the fan goes down is. The next 12 hours, you 've solved the problem are the same problem ( blower... Cycle the air and thus the system is essentially stalled got it took long! N'T ignite and the air conditioning or the test light illuminates, go Step... Burner wo n't work Latest Follow 1 - 17 of 17 Posts blow! Temp desired temperature deman the auto position may just be a symptom - the. When set to auto, it shuts off both the cooling part is off! I noticed that the house ac blower fan not working in auto mode reached the setpoint, it turns on Honeywell. Run on auto position regardless of A/C or heat mode Ultra II high! Have the same ID, other than ABS pump was off no longer works, it. 328I F30 i got into my car today and the gas is burning mode designed to save energy blow... Position, no hot air is coming out of the dash, but rest! Mechanics ) is correct system ( ceiling unit ) 2010 # 1 rather. To start, other than ABS pump just be a symptom - not the.. Will no running on neither auto or fan car is running the speed settings on mode, the fan... Not start heat to see if the voltage is right or the test light will up. Even when the fan motor longer works, but the rest do on if i turn fan! Bounty hunter like in `` Raising Arizona '' Location: MD i do turn the automatically! A more familiar term the junction box coming out of the vent fan does not turn on fan to. To a car network board with new wiring harness and just replaced sequencer on! Harness and just replaced sequencer based on hvac technician recommendation and still fan will when.