I recently bought a 2011 Jeep grand Cherokee 70th anniversary with 100k. The first thing I noticed was after I would start up the Jeep the air would blow full blast for one minute then it would stop for 6 seconds then automatically come back on full blast for one minute, etc. It does that on and off about four times for a total of 5 minutes. Then works fine till the next time the car is turned off/on. The next problem I noticed is there is no heat on the drivers side vents no matter what I set the temperature at it only comes out as outside temp. The knob used to go from feet to head to defrost works fine, just no heat. Passenger side works perfect. Any help would be greatly appreciated
No heat on drivers side/ Air blows on and off when started
- Thread starter Nated0323
- Start date
Mine also does the starting/stopping in heat mode. But I have zero heat on the drivers side, I would think the heat issue wouldn’t be the blower but who knows. I know I’ll be needing the heat in a few months so trying to pinpoint this issue without spending too much time or money
Last edited:
superj
Well-known member
you have a blend door that is not operating properly to the driver side of the truck. the one that stops the outside air and takes air form the heater core is not working. it could be vacuum operated or electric, i am not sure on your truck. and it could just be broken even though the power source is working.
until you get in there, you won't know though
until you get in there, you won't know though
It sounds like you're dealing with two issues, both potentially related to the HVAC system. For the first issue with the air blowing on and off at full blast during startup, this could be due to a malfunctioning HVAC control module or a problem with the blower motor resistor. The system might be misinterpreting signals and causing the fan to behave erratically. A reset of the HVAC control module or even reprogramming it at a dealership might help.
For the second issue with no heat on the driver’s side, this is a classic symptom of a faulty blend door actuator. The blend door actuator controls the flow of hot or cold air to different zones, and if it's stuck or malfunctioning, it can prevent heat from reaching the driver's side vents. The passenger side working fine suggests the actuator controlling the driver's side may need replacement.
I'd suggest starting with the blend door actuator for the heating issue, as it's a common fix on these models, and looking into the HVAC control module or resistor for the fan issue.
For the second issue with no heat on the driver’s side, this is a classic symptom of a faulty blend door actuator. The blend door actuator controls the flow of hot or cold air to different zones, and if it's stuck or malfunctioning, it can prevent heat from reaching the driver's side vents. The passenger side working fine suggests the actuator controlling the driver's side may need replacement.
I'd suggest starting with the blend door actuator for the heating issue, as it's a common fix on these models, and looking into the HVAC control module or resistor for the fan issue.
FIXED
It was the drivers side blend door sticking. I replaced the actuator first, that did nothing. I ended up having to modify the lower actuator gear with a screw on the heat side so the door wouldn’t get stuck closed. That fixed BOTH of my issues! So the blower turning on and off must have been a result of the door malfunctioning. I’m hoping I don’t have to take everything apart again. The biggest pain was the actuator screws. There’s a ton of info out there on replacing the actuator and gears but not this modification. Thanks for the help
It was the drivers side blend door sticking. I replaced the actuator first, that did nothing. I ended up having to modify the lower actuator gear with a screw on the heat side so the door wouldn’t get stuck closed. That fixed BOTH of my issues! So the blower turning on and off must have been a result of the door malfunctioning. I’m hoping I don’t have to take everything apart again. The biggest pain was the actuator screws. There’s a ton of info out there on replacing the actuator and gears but not this modification. Thanks for the help
