There has been a bit written about the right hand heater lever sticking.
Here is a comment made in another post by rwmastel some time ago for references
"There are two red controls.
- The one on the left side (driver's side in USA) controls the valve in the heater core, so it is like the "master" heat lever that turns the heat on/off for the whole car.
- The one on the right side controls a flap that allows heat to the right side of the car IF the "master" heat lever is on.
- Turn these away from the red dot (wedge?) to turn heat off.See
http://www.sl113.org/forums/index.php?topic=2545.0Another lever, with up/down arrows, controls from which vents the air flows.
Another lever contorls (open/close) the fresh air flap that is between the hood and windshield.
Your heater core valve may be stuck open, or the cable from the control may be disconnected. If your car is old enough, there MAY NOT BE an access hole (covered by rubber plug) in the firewall for this valve.
We have a wiki technical manual in progress, here is a link from that regarding heater levers:
http://www.sl113.org/wiki/pmwiki.php?n=Electrical.ReplaceHeaterLeaversYou can also search the forum messages for information using the "Search" link in the top right corner of the screen. These might be helpful.
http://index.php?topic=6070
http://index.php?topic=2514
http://index.php?topic=3681
If the primary heater slide doesn't move (the one that opens and closes the heater valve --- check the heater valve... most likely culprit or the linkages to it are frozen.
Also see
http://www.sl113.org/forums/index.php?topic=2545.0In my case I had a sticking heater lever and accessed it from the top through the speaker opening bu removing the wood vent, removing the speaker and then had access to the inner control levers and found that one was broken that was jamming up the lever action rather than a stuck valve.
Good luck
Garry