I have a 2003 silverado the left side blows cool air the right side works great. sometimes I can move the temp from hot to cold then back to hot and left side works OK for a day or so , but its real cold out and I would like to fix the left side heat controll Any suggestions ?

 

Great to hear from you joe0072! Welcome

 

Probably your blend door actuator needs to be replaced.

 

where is the blend dor actuator located ? Where can I get a picture or diagram of componets of heater assy for 2003 silverado

 

The blend door actuator is under the dash. Go to Youtube and do a search and you can see it being replaced.