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2007 Cadillac Escalade ESV Base AWD 4dr

2007 Cadillac Escalade ESV
Trim Info:
AWD, 4 Door
13 mpg city / 19 mpg hwy
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July 26, 2011, 3:03 pm

Norman A
 

Question: help changing A/C actuator

driver side a/c blows hot sometimes. I need direction (diagram) on how to change the actuator.


August 1, 2011, 9:10 pm

Tyler O
Expert Mechanic

You'll need to remove the dash to replace any HVAC motors.



First read the fault codes in the HVAC control module. It might tell you specifically which motor is having a problem etc.

AIR DELIVERY

HVAC CONTROL COMPONENTS

Mode Actuator
The mode actuator is a 5 wire bi-directional electric motor that incorporates a feedback potentiometer. Ignition 3 voltage, low reference, control, 5 volt reference and position signal circuits enable the actuator to operate. The control circuit uses either a 0, 2.5 or 5 volt signal to command the actuator movement. When the actuator is at rest, the control circuit value is 2.5 volts . A 0 or 5 volt control signal commands the actuator movement in opposite directions. When the actuator shaft rotates, the potentiometer's adjustable contact changes the door position signal between 0-5 volts .

The HVAC control module uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets a commanded, or targeted, value, the control signal is changed to either 0 or 5 volts depending upon the direction that the actuator needs to rotate to reach the commanded value. As the actuator shaft rotates the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module changes the control signal to 2.5 volts .

Auxiliary Mode Actuator
The auxiliary mode actuator is a 3 wire bi-directional electric motor. Ignition 3 voltage, ground and control circuits enable the actuator to operate. The control circuit uses a 0-12 volt linear-ramped signal to command the actuator movement. The 0 and 12 volt control values represent the opposite limits of the actuator range of motion. The values in between 0 and 12 volts correspond to the positions between the limits.

When the auxiliary HVAC control processor sets a commanded, or targeted, value, the control signal is set to a value between 0-12 volts . The actuator shaft rotates until the commanded position is reached. The module will maintain the control value until a new commanded value is needed.

Air Distribution

Mode Actuator
The mode actuator is an electronic stepper motor with feedback potentiometers. The HVAC control module sends signals to the mode door actuator through the mode door control circuit. Zero volts drives the actuator in one direction while 5-volts moves the actuator in the opposite direction. When the actuator receives 2.5-volts, the actuator rotation stops. A 5-volt reference signal is sent out over the 5-volt reference circuit to the mode actuator. When you select a desired mode setting, logic determines the value of the mode actuator signals. The HVAC control module's software uses this reference voltage in order to determine the position of the mode actuator through the mode door position signal circuit. The motor moves the mode door to the desired position.

Air Temperature

Air Temperature Actuator
The air temperature actuators are a 5 wire bi-directional electric motor that incorporates a feedback potentiometer. Ignition 3 voltage, low reference, control, 5 volt reference and position signal circuits enable the actuator to operate. The control circuit uses either a 0, 2.5 or 5 volt signal to command the actuator movement. When the actuator is at rest, the control circuit value is 2.5 volts . A 0 or 5 volt control signal commands the actuator movement in opposite directions. When the actuator shaft rotates, the potentiometer's adjustable contact changes the door position signal between 0-5 volts .

The HVAC control module uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets a commanded, or targeted, value, the control signal is changed to either 0 or 5 volts depending upon the direction that the actuator needs to rotate to reach the commanded value. As the actuator shaft rotates the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module changes the control signal to 2.5 volts .

Auxiliary Air Temperature Actuator
The auxiliary air temperature actuator is a 3 wire bi-directional electric motor. Ignition 3 voltage, ground and control circuits enable the actuator to operate. The control circuit uses a 0-12 volt linear-ramped signal to command the actuator movement. The 0 and 12 volt control values represent the opposite limits of the actuator range of motion. The values in between 0 and 12 volts correspond to the positions between the limits.

When the auxiliary HVAC control processor sets a commanded, or targeted, value, the control signal is set to a value between 0-12 volts . The actuator shaft rotates until the commanded position is reached. The module will maintain the control value until a new commanded value is needed.


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