Blower motor only works on high - 2500 Chevrolet Cars & Trucks

The blower motor relay is energized when the Blower Motor Control is set to the High position. This removes the blower motor resistors from the circuit and battery voltage is then applied directly from the HVAC BLO fuse (RH IP Accessory Wiring Junction Block) to the blower motor though the relay switch contacts. The blower motor then runs at high speed.

HVAC Blower Controls Circuit Description
The blower motor is a variable speed motor. The motor operates at a higher rate when voltage is increased to the maximum level.
The blower motor resistors reduce the voltage supplied from the A/C FAN fuse (LH IP Accessory Wiring Junction Block) when the blower control is set at low and medium speeds (speeds 1-4). The blower motor relay is energized when the Blower Motor Control is set to the High position. This removes the blower motor resistors from the circuit and battery voltage is then applied directly from the HVAC BLO fuse (RH IP Accessory Wiring Junction Block) to the blower motor though the relay switch contacts. The blower motor then runs at high speed.

Most likely the blower motor resistor or the fise for the low speeds. The high setting for the blower motor is on a separate circuit than the other lower settings.

look in the fuse panel there is a fuse for blower high and blower low check the one for blower low the location is on the inside of the fuse box lid

Its faulty blower motor resistor. The low and medium speed on blower motor is controlled by resistor and its actual speed is high. So because resistor is not working, blower motors actual speed which is high is working.

It can be faulty blower motor or faulty blower motor resistor. Get the blower motor inspected. If it's faulty it has to be replaced.

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For blower motor testing and replacing, check the link below: ----

Blower motor Testing/replacing for all vehicles?

http://repairhelpcenter.blogspot.in/2012/02/blower-motor-replacing-for-all-vehicles.html

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These will help.

Thanks.

Its faulty blower motor resistor. The low and medium speed on blower motor is controlled by resistor and its actual speed is high. So because resistor is not working, blower motors actual speed which is high is working.

It can be faulty blower motor or faulty blower motor resistor. Get the blower motor inspected. If it's faulty it has to be replaced.

=======

For blower motor testing and replacing, check the link below: ----

Blower motor Testing/replacing for all vehicles?

http://repairhelpcenter.blogspot.in/2012/02/blower-motor-replacing-for-all-vehicles.html

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These will help.

Thanks.

HEATER BLOWER MOTOR

Its faulty blower motor resistor. The low and medium speed on blower motor is controlled by resistor and its actual speed is high. So because resistor is not working, blower motors actual speed which is high is working.

It can be faulty blower motor or faulty blower motor resistor. Get the blower motor inspected. If it's faulty it has to be replaced.

=======

For blower motor testing and replacing, check the link below: ----

Blower motor Testing/replacing for all vehicles?

http://repairhelpcenter.blogspot.in/2012/02/blower-motor-replacing-for-all-vehicles.html

------------

These will help.

Thanks.

This is a problem that is due in every case to a failed blower motor speed control resistor. the blower motor resistor is located right next to the blower motor and the wiring harness connector sticks out of the air ducting that cools it.

Hi!!
The Blower Motor Resistor also called Manual Temp. Control resistor), is fried, replace. The price with floor console $25 and without floor console $65. here is a pic.


the resistor is located on the blower motor housing, fastened by two screws. It is the part where the electrical plug connects, the plug on the pic. goes to the blower motor.
A HELPFUL - 4 THUMBS rating for this solution would be greatly appreciated. Thank you for using FixYa.

does the motor not work at all or only on high setting? if only on high setting, i would recommend replacing the blower motor resistor. if it does not work at all, i would check the blower motor fuse first, if that has power, i would unplug the blower motor, key in run, and turn the fan on, then check for power at the blower motor connector, then check for ground, if both present, then replace the blower motor.

more than likely yes the resistor