The heater-cooler system on a single zone car is operated with a single motor, but the dual zone system has a motor for each side so that the air can be controlled separately. First, unhook and separate the negative battery wire and after that take the instrument panel out. To work on the driver side, remove the two holding screws from the back of the HVAC housing, separate the actuator from the housing and disconnect the HVAC wire harness. When installing, secure the actuator to the housing, line up the splines on its shaft with the blend door lever, tighten the screws to 2.2 N.m (20 in. lbs.), attach the HVAC harness once more, replace the instrument panel and attach the negative battery cable. With the side for two zones, after unplugging the battery and taking off the panel, disconnect the blend door lever from the output shaft and linkage, then unscrew the blow door actuator and bracket assembly from the HVAC housing and take off the assembly. First, mount the blend door actuator and bracket assembly on the HVAC housing, use screws tightened to 2.2 N.m (20 in. lbs.), reconnect the HVAC wires, match the guide pin on the blend door lever with the balance linkage guides, attach the lever to the actuator output shaft, fit the actuator in place under the instrument panel and reconnect the negative battery cable.