2005 GMC Sierra Hi

an actuator isn't working for modes meaning like floor deforst etc. try pulling fuse for 60 seconds with key on then reinstall it may reset the actuator to work if not you will need the actuator

Do you know which side the actuator is on ?? passenger or driver

I fgt in first reply you pull the hvac fuse inside truck try that first. see pic for actuator although there are tw different types you need to know if you have d07 or not that should be on glove box sticker.

Thanks it work when i pulled the fuse for 60 sec