Blower for hvac will not work? - 2006 Hummer H3

It's probably not going to be a fuse issue , you people have limited thinking because you have no clue how the electronic's work on your vehicles . The HVAC contol module as battery supplies yes , but control the blower motor with PWM - pulse width modulation controller .

Blower Motor Control Processor
The blower motor control processor is an interface between the HVAC control module and the blower motor. The blower motor speed control, battery positive voltage and ground circuits enable the control processor to operate. The HVAC control module provides a pulse width modulation (PWM) signal to the control processor in order to command the blower motor speed. The processor supplies 12 volts to the blower motor through the blower motor voltage supply circuit. The control processor uses the blower motor ground as a low side control to adjust the blower motor speed.

Most of the time the Blower Motor Control Processor is bad , without testing this is just a guess . Your best bet , take your vehicle to a qualified repair shop.

Have you checked voltage and ground for blower motor? in the diagram, the top wire at blower motor is voltage. The purple wire, bottom wire from blower motor is ground. You can see blower fuse at the top, hot all the time. The blower motor on/off, different speeds are controlled on the ground circuit. You can take two wire connector loose from blower motor, use both ends of test lite at wiring connector terminals, turn on key, turn on hvac and blower controls, if the lite comes on, you have voltage and ground. If good voltage and ground with no blower action, suspect the blower motor. I couldn't post whole diagram and make it readable. The problem could be almost anywhere, with the wiring? I can only help with testing. good luck

Hi, first you check the blower control panel and test the blower switch and potanssiumeter

Blower motor control module , maybe. The HVAC control panel sends a PWM - pulse width modulation control .

HVAC Blower Motor Circuit http://www.bbbind.com/free-tsb free wiring diagrams . Enter vehicle info. year , make , model an engine . Under system click on HVAC ,then under subsystem click on HVAC controls . Click the search button , then the second blue link . Blower motor control diagram . Suggest you take it to a qualified repair shop if you don't know how to diagnose electrical systems on automobiles

Which system ?
HVAC Systems - Manual HVAC Systems - Automatic
If automatic it's probably the blower motor control processor .
Blower Motor Control Processor The blower motor control processor is an interface between the HVAC control module and the blower motor. The blower motor speed control, Blower motor speed signal, battery positive voltage and ground circuits enable the control processor to operate. The HVAC control module sends the commanded blower motor speed to the control processor through a 0 to 12-volt linear ramped blower motor speed control circuit. As the blower motor speed control voltage increases, the blower motor speed increases. The control processor sends the actual blower speed to the control module through a 0 to 12-volt blower motor speed signal circuit. The processor supplies 12volts to the blower motor through the blower motor voltage supply circuit. The control processor uses the blower motor ground as a low side control to adjust the blower motor speed.

Either its the resistor or the motor itself.


SUV Performance Parts

steve, have you tried checking the blower motor resistor in the blower motor itself to see if its burnt?

Which of these systems does your vehicle have ?
HVAC Systems - Automatic
Blower Motor Control Processor
The blower motor control processor controls the speed of the blower motor by increasing or decreasing the voltage drop on the ground side of the blower motor. The HVAC control module provides a voltage signal to the blower motor control processor over the blower motor speed control circuit. As the requested blower speed increases, the HVAC control module increases the amount of time that the speed signal is modulated to ground. As the requested blower speed decreases, the HVAC control module decreases the amount of time that the signal is modulated to ground.

HVAC Systems - Manual
Air Speed - Front Control
The blower motor forces outside air into the vehicle's interior. The vehicle operator determines the blower motor's speed when the driver places the blower switch in one of 5 blower speeds. The blower motor will always operate in any switch position other than OFF, as long as the ignition switch is in the RUN position. The blower motor and mode switches are located within the HVAC control module. The blower motor OFF input is connected in series with the HVAC control module by the off blower motor control circuit.
Depending upon the selected speed, power is provided to the blower motor from either the ignition 3 voltage or battery positive voltage circuits from the fuse block. The battery positive voltage circuit only provides power when the High blower switch position is selected. Power and ground are provided to the HVAC control module by the ignition 3 voltage and the ground circuits.
Low Blower Speed
When the Low 1 blower speed is selected, the HVAC control module applies voltage to the blower motor resistor assembly through the low blower motor control circuit. Voltage is divided between 4 series resistors, a blower relay, and the blower motor to achieve the desired blower speed. The blower motor is grounded through the ground circuit.
Medium Blower Speeds
When the Medium 1 blower speed is selected, the HVAC control module applies voltage to the blower motor resistor assembly through the medium 1 blower motor control circuit. Voltage is divided between 3 series resistors, a blower relay, and the blower motor to achieve the desired blower speed. The blower motor is grounded through the ground circuit.
When the Medium 2 blower speed is selected, the HVAC control module applies voltage to the blower motor resistor assembly through the medium 2 blower motor control circuit. Voltage is divided between 2 series resistors, a blower relay, and the blower motor to achieve the desired blower speed. The blower motor is grounded through the ground circuit.
When the Medium 3 blower speed is selected, the HVAC control module applies voltage to the blower motor resistor assembly through the medium 3 blower motor control circuit. Voltage is divided between a series resistor, a blower relay, and the blower motor to achieve the desired blower speed. The blower motor is grounded through the ground circuit.
High Blower Speed
When the High blower speed is selected, the HVAC control module applies voltage to the blower motor resistor assembly through the high blower motor control circuit. The voltage energizes the blower relay, causing the blower motor to be connected directly to the battery positive voltage circuit. The blower motor and blower motor relay are grounded through the ground circuit.

HVAC Control Module
The HVAC control module is a class 2 device that interfaces between the operator and the HVAC system to maintain air temperature and distribution settings. The battery positive voltage circuit provides power that the control module uses for keep alive memory (KAM). If the battery positive voltage circuit loses power, all HVAC DTCs and settings will be erased from KAM. The body control module (BCM), which is the vehicle mode master, provides a device on signal. The control module supports the following features:

"2007 chevy tahoe ltz--rear air works ---front air does not work." Hi! I guess you are referring to the front hvac blower not blowing air at any speed and not coming out at any vents at any mode position. If this is the case, you can start with the fuses at the underhood fuseblock. Check out the three hvac labeled fuses. If found okay, and the hvac controller on your dashboard seemed to be working normally, you better check out your front hvac blower motor underneath the right IP section. You need to verify if power is reaching your front hvac blower when requested by the a/c blower controller. I hope you get lucky. If this is not for you, perhaps a few more detailed symptoms would be helpful. : )

replace the "blower motor resistor" located next to the blower motor