When I went back to the car to leave, the fan was off. In air conditioner auto mode designed to save energy and blow ur air as per temp desired temperature deman. I have tried cooling, heating and plain fan but the fan does not start. Blower will no running on neither auto or fan. Rotated all the unmarked relays around in the junction box. 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. 2. If you manually had to turn the fan on by cutting the switch to on and not auto then you need to replace the fan switch which controls fan by tempature. If not, skip to Step 4. My capacitor and transformer is also good too. Vocational, Technical or Trade Scho. I slid the thermostat switch to HEAT to see if the fan/blower would work in that position. Low speed blower won't work in auto mode. To diagnose why the air conditioning in your car isn't working, start by turning your car on and setting the AC to full blast. Wouldn't want to suggest throwing parts at it. Jump to Latest Follow 1 - 17 of 17 Posts. One of those settings is better than the other. It drives the fan but also turns the AC on when necessary, etc. Keeping the black lead on a good ground, usually a bolt on the engine block, and the blower switch turned on, use the red lead to probe the plug that usually attaches to the blower motor. Douglas. started getting cold again and it’s playing up. The AC compressor outside works fine. I’m having similar issues with my R58. I’d jumped the motor and is working. Then turn the AC back on to test it. All through summer no problems. Is … read more. There is no battery to operate the blower. Vince vlee1973, Oct 28, 2010 #1. 3,119 satisfied customers. 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. 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 the fan is in the auto mode, the air conditioner moves air only when the cooling part is running. 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. Rotated all the PDC relays around, they have the same ID, other than ABS pump. It took 15 minutes for the job. The "blower" and the "fan" are the same things. When I got the car, the climate control didn't work. 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). I have replaced the hedgehog (voltage regulator/ resistor) but still no joy. Thatguy Homeowner. I hear it respond when I change the speed settings. Since the vehicle is new (Indica Vista QJD - Aura) got it done under warranty. No blowers for first 10 mins of any drive then it all starts working again. Blower still does not work. Though while turning on the heat, the ignition happens and the ignition fan runs but the blower fans does not. There is no "Off" setting on the Honeywell thermostat, just ON and AUTO. 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. When I set it to COOL with Fan set to AUTO, it turns on the A/C and the fan automatically. We used the word "fan" in the problem description because it's a more familiar term. 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. Any help would be greatly appreciated. The fan is running. Does the AC turn on at all? I'm having the same problem with my heater blower not working, I have a Citroen C4 2005 1.6 Vtr+ coupe, had it's M.O.T recently and to my surprise the heater blower didn't work on any setting, Asked the garage if they had done anything accidently but no, due that I've had the car S/H since nearly new 8 months. Just cool air blows. As a side note, I was a bit worried of fire if the blower did not turn on. 1 - 17 of 17 Posts. Like on mine, the lowest fan speed no longer works, but the rest do. I have a TRANE XE 90 blower with furnace and AC. If the relay board isn’t working properly, the fan might not run. When I do turn the fan to the ON position, no hot air is blowing out of the vent. I tried changing from top to middle to bottom vents. When the fan's in the on mode, the fan keeps running continuously, even when the cooling part is turned off. There are several causes for the heater not activating, and you can troubleshoot the problem yourself before calling in a technician. Continue with Google . Reply. Furnace Blower Fan Wont Turn Off - Hello Richard, I have a problem with my furnace where the indoor blower will turn off. When I set it to COOL with Fan set to AUTO, it turns on the A/C and the fan automatically. This occurs whether it's the air conditioning or the heater is switched on. The fan doesn't run well. The circulation fan on this has stopped running. The relay board provides voltage to many components of the air conditioner, including the fan motor. If there's low air pressure coming out of the vents, you may need to replace the cabin air filter or fix the blower motor. So for some reason, the AUTO fan mode does not work. My home AC fan blower does not work in AUTO mode, but it does work when I slide the switch to ON. The official name for it (as used by mechanics) is "blower". I believe the wiring (5-wire) is correct. The fan mode for central air conditioning systems is entirely different from the fan mode for window-box air conditioning … Blower still does not work. I noticed that the vent fan does blow on the first 2 fan settings but nothing after that. I bet that thing has 'smarts' because it has a CAN interface - that's the equivalent to a car network. However, it blows normal in defrost mode. It was -15F and when I started the car, the fan was on, but a little squeaky. Continue with Facebook. I have Ultra II 90 high efficiency furnace maid by Magic Chef. Also, the furnace is hot and the gas is burning. Cold air is coming out of the dash, but it is very weak out of the vents. They always mount the interior fan near the evaporator and heater cores. Good. However, the fan will work when the thermostat is set to the ON position. Joined: Aug 27, 2008 Occupation: A bounty hunter like in "Raising Arizona" Location: MD. My furnace seems to be heating okay it is just the blower will not shut off. Thermostat Q - Blower Does Not Turn ON in FAN Auto Mode. Heating and cooling work fine, but the blower fan won't stop running for 30+ minutes after the heating or cooling turns off. Depending on the year, make, and model you may find this component both in the interior cabin area or outside in the engine compartment side of the firewall. There's a switch or something located under the blower fan that goes bad, and not all the fan speeds will keep working. 2013 328i F30 I got into my car today and the air is not working. I replaced the thermostat and get the same results. I read few posts here and then went to the Service center and got the same reply " BLOWER resistor " gone and needs to be replaced. It started last winter with the blowers not working on cold mornings. I have 120V incoming power to … replaced board with new wiring harness and just replaced sequencer based on hvac technician recommendation and still fan will not run on auto position. Checked continuity of 40 amp blower fuse; it's okay. I just installed a NOMA 7-day programmable thermostat for an electric furnace/AC system (ceiling unit). Like on mine, the lowest fan speed no longer works, but the rest do. If strange noises are coming from the AC, there could be an issue with the compressor and it may need to be fixed or replaced. The fan mode and switches are one such example. 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. When the fan goes down there is no way to cycle the air and thus the system is essentially stalled. The AC runs but the circulation fan fails to start. Save Share. It seems that once it gets hot outside, say over 90 degrees or so, and the car is sitting in the Texas sun the blower motor won't kick in. If the voltage is right or the test light illuminates, go to Step 3. The Mercedes has a series of sensors that, working in concert with a computer, maintain a constant climate in response to the settings on the console. While each component in a central air-conditioner is critical, quite simply the unit will not work if the fan is not running. When the thermostat senses that the house has reached the setpoint, it shuts off both the cooling and the fan. The blower will turn on if I turn the thermostat to the fan position. Another common symptom of a faulty blower motor resistor is a a blower motor that does not function on certain settings. This is my wife's car so I'm rather baffled as to why this behavior is occurring. It is an older furnace, and I have checked the thermostat settings. The fan works just fine when set to AUTO with the AC but not with the heat. Fans in the central A/C both pull air out of the room to be conditioned and have humidity removed and also push chilled air through the vents throughout the house. this unit has small rocker switch on front panel for auto/on operation. My blower will not come on neither heat or cooling mode. Even i faced the same problem (AC blower fan stopped working on first two settings )while traveling from Pune to Aurangabad. Hello my blower motor will not work in auto position regardless of a/c or heat mode. If it does not, that fan not running right may just be a symptom - not the cause. You could hear that the heater valve was working and that the compressor fan was kicking on with AC buttons, but no air would blow out of the vents. The ac blower motor is usually located in the AC duct housing or heater case assembly. If it works for the next 12 hours, you've solved the problem. This is a 1999 Malibu. Good. I believe the wiring (5-wire) is correct. If the blower … Join the discussion. 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. Blower fan not working when hot outside? Before we focus on the motor and controls of the air handler blower fan (used in both air conditioning and heating systems) let's ask if the trouble is not specifically the blower fan but more basically: the air conditioner or heater itself just won't start in response to a call for cooling or heating. The meter should read between 9 and 11 volts or the test light will light up. Last year had to replace circuit board because it shorted out. Hello, I have heat pump unit with a backup auxiliary heat. Checked for battery at the blower, when the car is running. *a little context* The car ran okay when I got it took a long time to start when cold. What happens when the burner won't ignite and the fan won't blow warm air into your house? My furnace fan/blower will not work when set to the auto position. 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