heater stopped working (of course)
 

coolant ok, thermostat ok, fan blows, AC works, just no warm air. I can track it down but its probably a quick fix (like a vent opening) for someone who knows what they are doing. I had this problem a year ago and can't remember what I did to kick it on.

I just had the opposite problem happen... it won't stop blowing hot air (much like myself). I think my problem is a broken connector on the lever deal... You might do a search for "blows hot air," as the broken connector could be your problem too... it could be just broken in the cold position.

if the plastic holder under the dash breaks, it falls shut, putting it to full heat. I read on here its a failsafe designed so if the climate control busts, it will keep you from freezing in those horrid german winters.

I had the same problem. The vacuum controled valve behind the motor, right where the heater hose comes off the back of the block and snakes along the wall before going into the car, fell out of its plastic holder, and it wasnt controlling the flow. When it pops out it shuts the flow off, and no hot antifreeze enters the car. Same thing would happen if you took the vacuum line off. I just pushed mine back into the clips (i guess i didnt put it back in securely enough when I did the clutch) but i have no problems with heat now.

Your Heater control valve probably failed - it is that bulbous object on the heater pipe, rught behind and to the left of the distributor.

AFJuvat

Just had the same prob on mine. It was the plastic connectors on the damper lever under the dash