The ATF in the vacuum lines for the HVAC air flow mode actuators caused a vacuum blockage and could not change the actuators for the air flow. I traced the trans fluid to a defective vacuum switch on top of the 4WD transfer case, which has common vacuum lines with the HVAC system. I cleaned out the vacuum lines, replaced the vacuum switch on the transfer case then added more ATF and replaced one HVAC vacuum actuator for the defroster.
A D V E R T I S E M E N T S
The ATF in the vacuum lines for the HVAC air flow mode actuators caused a vacuum blockage and could not change the actuators for the air flow. I traced the trans fluid to a defective vacuum switch on top of the 4WD transfer case, which has common vacuum lines with the HVAC system. I cleaned out the vacuum lines, replaced the vacuum switch on the transfer case then added more ATF and replaced one HVAC vacuum actuator for the defroster.
- David C., Highland, MI, US