Coolant smell in 2003 Trailblazer

There is the smell of coolant in the vehicle without the heat being on. Also feel heat coming from the drivers side. If I push the recirc button everything is fine. No leaks anywhere. Two seperate garages checked for leaks and tested heater core. Heater core is fine and no leaks. Coolant levels are fine.
They suggested that there is a bad actuator that won't let some door open to let the heat out. That door is behind the dash which has to be removed to get access to it. They didn't recommend taking the dash out due to the cost involved. Has anyone ever heard of this problem? :screwy:

Seperate issues, the mode door actuator has been a common problem , but this does not generate a coolant smell in the truck. There is a new procedure released by GM to bypass removing the dash to replace the actuator.

Thanks! I've taken the vehicle to a Chevy dealer, also an independant garage.
Where should I go from here?