# Heater on 4 doesn't work; blow motor works on all settings but number 4.



## provost (Oct 19, 2011)

Hello,

My blow motor will run at setting 1, setting 2, and setting 3, but no go on setting 4, the strongest setting.

I have tried using a known good resistor, pulled one out of another sentra that blows on all 4, and that didn't solve it.

So I tried replacing the blow motor switch, with one from a parts car, and that didn't work either. The fuses are good. Everything seems good, it just won't blow on 4.

Is this a problem with the blow motor, where it cannot pull enough electricity to run on 4? Or is there something I'm missing that could be broken, stopping it from working on 4. Any help is appreciated, I've been trying to fix this all week.


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## dreamteam (Jul 29, 2005)

Use a good piece of wire to jump 12 volts to the blower motor.
Does it run, does it seem faster?
If so, trace the wires for the heater circuit.


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## provost (Oct 19, 2011)

How should I jump it? Can I connect it straight to a car battery?


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## smj999smj (Jan 1, 2006)

The resistor doesn't play a part in fan speed #4. Unplug the 6-pin harness connector from the fan switch and use a test light to check for power at the blue w/ white stripe wire with the key "on." If you have power there, jump it to the black wire of the same connector. If the fan runs, replace the switch. If you don't have power at the blue/white wire, you have an open between the harness connector and where the blue/white wire splices with the blue/white wire lead to the blower resistor. You'll have to trace the circuit and repair it. If you have power at the blue/white wire at the switch connector and when you jump it to black, it still doesn't run the motor, I would check and make sure both fuses are good for the blower fan in the fuse box (you may want to check that first) and then look for excessive resistance in the blue/white wire circuit.


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## 1badz28 (Jul 14, 2008)

funny cause mine works on all settings except #1


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