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Blower motor relay/resistor, where is it ?

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Old 04-15-2009, 12:24 PM
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Default Blower motor relay/resistor, where is it ?

My heater works, my a/c works but the blower only blows on the highest setting. I am going to buy a relay/resistor but dont know where it is located ?? Cant see it in the Haynes manual.
Please tell me where it is... Thanks.
 
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Old 04-21-2009, 07:54 PM
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The blower motor resistor pack should be mounted to the HVAC housing under the hood. It will look like a piece of fiber board or plastic with an electrical connection coming out of it. The resistors themselves are cooled by the airflow within the HVAC system.
 
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Old 04-22-2009, 04:39 PM
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Does the resistor control the heat or the blower settings ?
I just need to get the blower blowing on the 3 lowest settings rather than having it blow on full all the time.
 
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Old 04-22-2009, 06:00 PM
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The blower motor resistor pack controls all but the high fan speed setting.
 
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Old 04-22-2009, 06:03 PM
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Originally Posted by swartlkk View Post
The blower motor resistor pack controls all but the high fan speed setting.

High fan speed setting being direct contact right? Or completely closed circuit? However you wanna say it?

Anybody ever though of using a variable frequency drive in this application? Better for the blower motor, less corrodable parts and less power usage?
 
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Old 04-22-2009, 06:08 PM
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For a VFD to work, you would have to be working with alternating current. Unless you were to convert from DC voltage to AC voltage and back again... A PWM (pulse width modulated) voltage supply would work, but would be much more expensive than the resistor pack and may cause some unwanted noise and wear in the motor as the voltage supply pulse hits each time. With a reduced voltage supply as a result of using a resistor, the power is constant to the motor.

The High setting goes through a relay, bypassing the resistor pack all together.
 
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Old 04-22-2009, 06:15 PM
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Originally Posted by swartlkk View Post
For a VFD to work, you would have to be working with alternating current. Unless you were to convert from DC voltage to AC voltage and back again... A PWM (pulse width modulated) voltage supply would work, but would be much more expensive than the resistor pack and may cause some unwanted noise and wear in the motor as the voltage supply pulse hits each time. With a reduced voltage supply, the power is constant.

The High setting goes through a relay, bypassing the resistor pack all together.
Maybe a VFD was the wrong term, I forgot you were an engineer, electronic speed controls for RC cars that provide power to motor in short bursts, of full power, versus limited power through the resistor. I was taught that limited power was bad for an electric motor as it cause the windings to heat up faster.

Not quite 480V but similar idea. Better for the motor itself.
 
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Old 04-22-2009, 06:22 PM
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Yeah, you meant PWM (pulse width modulation). It may be better for the motor, but that does depend on the design. As I said though, it may cause more wear in the bearings and/or more noise due to the modulated signal.
 
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Old 04-24-2009, 04:29 PM
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Is this the Resistor Pack ? It is in the catalogue as the Resistor .
 
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Old 04-24-2009, 06:34 PM
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Yep, that's it.
 

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