1998 Buick Park Avenue Ultra.
Engine size = 3800
New battery, and drivers side blend air actuator.
Question = Drivers side heat was not working. Was blowing out cold air. Replaced the temperature blend air actuator. Now the heat works but temp will not go cold.
Answer: You probably either installed the actuator in the wrong position, or you could have a bad part. The actuators usually only go on one way and have to sit on the temp door the proper way. Also, you may have not relearned the actuator positions. If the air conditioning control head doesn't know what position it's in, it cannot control it accurately. You can try resetting the system by either pulling the HVAC fuse or disconnecting the battery for a few minutes
Then start the car and do not touch any A/C controls for 2 minutes. If you have a scan tool accessible to you, you can reset the actuators that way. If that doesn't work, you should take the actuator off just to make sure it moves and is aligned properly, otherwise you have a bad part.