On my 2008 Yukon Denali the passenger side HVAC started blowing hot randomly, then all the time. Others have posted that this happened on the driver's side. The culprit is generally the respective blend door actuator. The driver's side blend door actuator is on the bottom of the HVAC and can be accessed from below behind the glove box - easy. The passenger side blend door is on the top of the HVAC and can't be easily accessed. Here's what I did:
1. took the bottom actuator off, took it apart, cleaned out the excessive grease (especially from the contacts that provide position feedback), reinstalled, and verified the actuator worked and this didn't fix the problem ;=)
2. bought a service manual online from tradebit.com - a great value
3. bought a set of plastic tools from Harbor Freight designed to pry loose the interior parts - also a great value
4. followed the service manual procedure to remove lots of dashboard parts including the top of the dashboard to get access to the passenger side blend door actuator (I didn't actually remove the top panel but raised it up to reach the actuator)
5. cleaned out the excessive grease from the top actuator & cleaned the contacts
6. reinstalled everything (swapped top & bottom actuators)
7. verified that the problem is fixed
Having completed this I think the passenger side actuator can be removed by removing the passenger side airbag and accessing through that hole, though I didn't verify this. This would save removing a lot of dashboard parts.
1. took the bottom actuator off, took it apart, cleaned out the excessive grease (especially from the contacts that provide position feedback), reinstalled, and verified the actuator worked and this didn't fix the problem ;=)
2. bought a service manual online from tradebit.com - a great value
3. bought a set of plastic tools from Harbor Freight designed to pry loose the interior parts - also a great value
4. followed the service manual procedure to remove lots of dashboard parts including the top of the dashboard to get access to the passenger side blend door actuator (I didn't actually remove the top panel but raised it up to reach the actuator)
5. cleaned out the excessive grease from the top actuator & cleaned the contacts
6. reinstalled everything (swapped top & bottom actuators)
7. verified that the problem is fixed
Having completed this I think the passenger side actuator can be removed by removing the passenger side airbag and accessing through that hole, though I didn't verify this. This would save removing a lot of dashboard parts.
