In the middle of my commute to work my blower for my heat stopped working. It won’t work for any of the speeds. I’ve replaced the blower motor, the resistor, and the relay. My two 15 fuses for the blowers are fine. I’m at a loss right now on what it could be. Anyone have this issue before? I live in Michigan and it’s freezing outside so I’m hoping for a quick fix that I may not be thinking of.
The fan speed switch itself? Is there 12V to it?
I have 12v to the blower
Set the blower speed to high, and then rap on the blower motor with the handle of a screwdriver.
If the blower starts working, the new blower motor is bad.
Blower motors love 12VDC… They love ground connections in equal measure. If you test power at the blower motor plug…and also notice that voltage responds to the switch (multi-meter time)…then you will know the switch is working properly. So then…you need to test your ground connection. After that…its up to the new blower motor assy to be in working order.
Rap on the blower motor?
The blower switch controls the ground for the blower motor, if there is no ground at the blower motor inspect the blower switch.
Am automobile blower motor is usually just a simple dc motor. It only has two inputs, power (12 v) and ground. Turning it on or off can occur either in the power or ground input. But if you measure 12 v between the two inputs right at the motor itself and it isn’t spinning, the motor is defective or there’s debris in the fan cage that is preventing it from spinning. Rapping (tapping) on the body of the motor (say with the plastic handle of a screwdriver) can sometimes make a malfunctioning one work. There’s electrical contacts inside the motor that go from on to off to on etc as the motor turns and sometimes they get stuck in between. Tapping can move it enough to get it working again.
When checking the voltage, I would get about 12v for the high speed and none for the lower speeds. When I turned it off I checked for continuity of the ground wire and it read OL. Does this mean I have a bad ground between the blower and switch or blower and resistor?
This must be the ground from the switch since I’m getting overload on all speeds when I have the power off. Does this mean I need to replace the switch?
Did you ever figure out what the problem was? I am in Virginia with an 80-degree heat Wave this week and my fan just died. I replaced the resistor and I hot-wired the fan motor and it seems to be okay.
If you have a Subaru check to see if power is getting to the motor when the fan speed is set to high. If you have voltage there then the trouble is on the return side of the circuit. The resistor pack and switch are on the ground return side of the motor connection. If you have no power to the motor then check the blower relay. I assume you have already checked the fuse for the blower.
The fuses we’re the first thing I checked. It has no fan relay, that I can find. The blower is not getting power unless I run a jumper wire to it. I have no idea how to test the switch. I did find a service alert that the switch can be damaged just taking the dash apart. https://subaru.oemdtc.com/340/hvac-control-panel-removal-precautions-2013-2016-subaru
You state that the blower doesn’t have power to it. I assume that you have already tested for power using a meter or probe at the connection to the motor. If that is correct then you most likely have a problem with the blower relay connection. I don’t have service data for your model but I am pretty certain there is a relay for the blower motor. In the older models I think the relay was located up under the dash area near the door jam. The switch turns on the relay by making a ground connection to the relay coil, which turns on the relay. The switch also applies ground for the return side for the motor circuit. At least that is the way the older models worked and I am assuming your model is designed the same way.