Blower motor not running after cabin leak
09-11-2024, 06:02 PM
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Blower motor not running after cabin leak
I own a 2010 G37 Convertible and recently the blower stopped working mid-drive.This is my first time doing any sort of self-diagnostics or working with electric/a multimeter, so I am hoping someone can point me to the next steps. Below is a summary of the issue and what I have tried so far:
1. The control panel continues to function, and the air gets cold, but the blower does not activate. The two 15A blower fuses were blown, so I replaced them, and they blew as soon as the car turned on. I discovered a leak from the windshield cowl which dripped directly through the cabin air intake and into the blower motor. Once I fixed the leak in the cowl and dried the blower motor, I replaced the fuses and they no longer blow when the car is turned on.
2. I've disconnected and tested the blower fan with wires connected to the battery and it seems to function properly, though there is visible rust from the water leaking. I tested the connectors which plug into the blower motor, and I believe they are good (my first time using a multimeter, so basing this off of what i've seen in youtube videos).
3. I pulled out the relay behind the fuses and it clicks when connected to a battery, and I believe there is continuity when powered (set the multimeter to ohms and got a reading between 0 and 1).
The blower still does not run, but the fuses no longer blow. I assume the leak is the cause of the initial issue, though there doesn't seem to be a short anymore. Any idea what else I can test? I'm not sure how to test the wiring from the fuse box to the blower motor, but I can figure that out if that could be the issue. I've read similar posts with AC Amplifier issues or resistor issues, but i'm not sure how to access those parts or whether the resistor is within the blower motor.
1. The control panel continues to function, and the air gets cold, but the blower does not activate. The two 15A blower fuses were blown, so I replaced them, and they blew as soon as the car turned on. I discovered a leak from the windshield cowl which dripped directly through the cabin air intake and into the blower motor. Once I fixed the leak in the cowl and dried the blower motor, I replaced the fuses and they no longer blow when the car is turned on.
2. I've disconnected and tested the blower fan with wires connected to the battery and it seems to function properly, though there is visible rust from the water leaking. I tested the connectors which plug into the blower motor, and I believe they are good (my first time using a multimeter, so basing this off of what i've seen in youtube videos).
3. I pulled out the relay behind the fuses and it clicks when connected to a battery, and I believe there is continuity when powered (set the multimeter to ohms and got a reading between 0 and 1).
The blower still does not run, but the fuses no longer blow. I assume the leak is the cause of the initial issue, though there doesn't seem to be a short anymore. Any idea what else I can test? I'm not sure how to test the wiring from the fuse box to the blower motor, but I can figure that out if that could be the issue. I've read similar posts with AC Amplifier issues or resistor issues, but i'm not sure how to access those parts or whether the resistor is within the blower motor.
09-11-2024, 07:03 PM
#2
There is a small "microprocessor" in the blower which receives the speed signal from the AC Amp which in turn, modulates the speed of the blower motor. While the blower may work when connected directly to the battery (ie. 100% duty), there is a strong chance the circuit board shorted out from the water intrusion which is causing the failure. It has happened several times before.
I doubt there are any issues with the electrics upstream of the blower (amp, control panel, wiring, etc.).
Best advice, just replace the blower and call it a day. You can go used OEM (eBay or junkyard) or get a new, inexpensive one off Amazon.
I doubt there are any issues with the electrics upstream of the blower (amp, control panel, wiring, etc.).
Best advice, just replace the blower and call it a day. You can go used OEM (eBay or junkyard) or get a new, inexpensive one off Amazon.
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