AC blower stopped working

[Kingwombat]

Hello all.  My AC blower stopped working on my 2013 Impreza hatchback.  Was driving with AC working fine, answered a bluetooth call and turned off fan to reduce noise.  When I hung up, fan wouldn't come back on.  Fan does not work at any speed. Checked all fuses for AC & blower and are fine, as well as relay under hood.

[Fairtax4me]

Check for power at the fan motor connector. And check for ground when the switch is operated.

If you have power and ground, the fan motor is the problem.

If you have power, but no ground, the switch or the fan speed control are the likely problem.

If you have ground, but no power, fuse, or relay would be at fault.

 

I wouldn't expect it on a vehicle that new, but sometimes the brushes in the fan motor get stuck and no longer make connection with the commutator on the armature. Usually a tap on the fan motor with a screwdriver handle will dislodge them and the fan works again temporarily. On some vehicles you can remove a cover on the fan motor and clean the area of the brushes and get the motor working properly again. Most newer vehicles the fan motor is not serviceable and just has to be replaced.

[Dan Kelley]

I have a similar situation with a 2015 Legacy 2.5 Premium with auto air and heat, but it is intermittent. The blower motor works fine after sitting overnight, but on a warm or hot day, especially after being parked in the sun, it does not come up to speed, no matter how high I have manually set the blower speed. It runs, but slowly, and the fan speed varies up and down, but never really a strong flow of air. I can hear the blower motor speed changing, so it isn't a HAVC door issue. Any ideas on weather I need a new motor (and if so, how difficult is this?), Blower motor control module/resistor, or do I just take it to the dealer?

 

Thanks for your help.

Edited August 28, 2017 by Dan Kelley

[idosubaru]

Check for power at the fan motor connector. And check for ground when the switch is operated.

If you have power and ground, the fan motor is the problem.

If you have power, but no ground, the switch or the fan speed control are the likely problem.

If you have ground, but no power, fuse, or relay would be at fault.

 

Wow, excellent, i've never seen it put that way before.  I need to save that!

 

I have a similar situation with a 2015 Legacy 2.5 Premium with auto air and heat, but it is intermittent. The blower motor works fine after sitting overnight, but on a warm or hot day, especially after being parked in the sun, it does not come up to speed, no matter how high I have manually set the blower speed. It runs, but slowly, and the fan speed varies up and down, but never really a strong flow of air. I can hear the blower motor speed changing, so it isn't a HAVC door issue. Any ideas on weather I need a new motor (and if so, how difficult is this?), Blower motor control module/resistor, or do I just take it to the dealer?

 

Thanks for your help.

 

If it's still under warranty take it to the dealer. 

 

If you live in, or the car has ever been in, an area with prevalent chipmunk or mice populations then you may want to check the blower fan/cage/duct area.  If there's no noise/debris then it's usually insulation they've chewed out and stuffed in there. 

 

I'm not an electrical wizard so hopefully fairtax responds again - but I'd check the voltage at the fan and see if it's normal and then give it 12 volts directly from elsewhere and see what it does.

 

In general the fans fail so rarely and are so easy to replace that used is a great option.  There's no demand (since they never fail) so they're basically useless to a yard.

www.car-part.com and you can have one on your door step in a few days for cheap. 

[Dan Kelley]

Thanks, Elite Master of the Subaru.

 

I have made an appointment with the dealer. Hopefully all will be corrected before it gets hot again here in New England.

[Fairtax4me]

I have a similar situation with a 2015 Legacy 2.5 Premium with auto air and heat, but it is intermittent. The blower motor works fine after sitting overnight, but on a warm or hot day, especially after being parked in the sun, it does not come up to speed, no matter how high I have manually set the blower speed. It runs, but slowly, and the fan speed varies up and down, but never really a strong flow of air. I can hear the blower motor speed changing, so it isn't a HAVC door issue. Any ideas on weather I need a new motor (and if so, how difficult is this?), Blower motor control module/resistor, or do I just take it to the dealer?

 

Thanks for your help.

Probably not a blend door/flap problem. Does the car have automatic climate control? Does the fan work properly if you set it on automatic and turn the temp all the way down to max cold? Or all the way to max hot?

Are the speed changes quick or gradual?

Have you ever changed the cabin air filter?

Agree it does need to go to the dealer for warranty. No reason a 2015 should have a possible fan motor or fan speed controller failure.

[Fairtax4me]

Wow, excellent, i've never seen it put that way before. I need to save that!

.

On older Subarus at least with the normal 4 speed fan control the blower fan gets power direct from the relay. Then the motor is grounded through the resistor and then through the fan speed switch in the HVAC control. So a non-functioning fan is typically an easy diagnosis just by checking for power on both sides of the fan connector. If you follow the wiring behind the glove box one wire comes out of the fan and goes straight to the resistor block a couple inches away, so it's easy to tell which should be hot and which should be "ground".

 

On newer cars with variable fan speed or automatic climate controls there is actually a small electronic module that controls the fan speed. Either the HVAC control panel or the ECU may command the speed controller. The controller may be on either the ground side or the power side depending on the car, so those get a bit trickier to test. Typically I test at the fan connector first, and if there is no power there I find the speed controller if possible and test for power there. The wires going to the fan will always be the larger of the wires at the controller, and one will usually match color of one on the fan. The other wires go to either the ECU or the HVAC control and are typically small and go to low amp computer circuits, so avoid testing those directly with a multimeter unless you have a wire diagram and good understanding of the control system which could be either power or ground or PWM of the speed control circuit to signal the change in speed.