No , there are no vacuum operated mode, temp. actuators ,there are all electric actuators . Is your lacrosse
Dual Zone Control ? Could be a stuck temp. control actuator . Do you get both heat an cold from that vent . I'm assuming it's a vent when you say grid . Does you lacrosse have manual or automatic climate control ?
Air Temperature Actuators
The air temperature actuator is a 2-wire bi-directional electric motor. Two control circuits enable the actuator to operate. The control circuits use either a 0 or 12-volt value to co-ordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 12 volts. In order to move the actuator, the HVAC control module grounds the appropriate control circuit for the commanded direction. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction.
The HVAC control module determines the door position by counting motor pulses on one of the control circuits. These pulses are small voltage fluctuations that occur when the brush is shorted across two commutator contacts as the motor rotates. As the actuator shaft rotates, the HVAC control module monitors the voltage drop across an internal resistance to detect the pulses. The HVAC control module converts the pulses to counts with a range of 0-255 counts. The HVAC control module uses a range of 0-255 counts to index the actuator position.
The replacement of
Temperature Valve Actuator Replacement - Left Side Is not difficult at all , Don't need to take the whole dash apart !
Remove the left closeout panel. Refer to Instrument Panel Insulator Panel Replacement - Left Side
. Disconnect the electrical connector from the left air temperature actuator. Remove the mounting screws from the left air temperature actuator.
Remove the left air temperature actuator.
This is view of left side actuator .