Mercedes: No heat in 420SEL, climate control unit, number search results


Question
The heat is no longer working in my 1988 420SEL.  The vents just blow out cold air regardless of the engine temperature or how long the car has been running.  It worked fine before, and I only noticed it a few months ago.  Thank you very much for your help.

Answer
Best guess:
* Low coolant = system leak.
* Bad mono valve diaphragm.
* Bad Sampler Blower Motor.
* Bad Climate Control Unit

Mono valve Problems
http://www.mercedesshop.com/shopforum/showthread.php3?p=1026761#post1026761


PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1988 Mercedes Benz 420SEL
Part: Mono Valve Repair Kit
 Note:  Heater Valve
Electromagnetic heater valve.     
R3023-15174 Mono Valve Repair Kit Bosch IN STOCK $49.45  
  
http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=merc...


PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1988 Mercedes Benz 420SEL
Part: Sampler Blower Motor
 Note:  
For Temperature Sensor Ventilation on roof rail. Draws air from a specific location in vehicle to sample the temperature and relays information to control unit which takes action to correct to desired temperature setting. Optional with 000 830 96 08.     
R3011-70122 Sampler Blower Motor IN STOCK $54.88  
  
http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=merc...


Vehicle: 1988 Mercedes Benz 420SEL
Part: Climate Control Unit
-------------------------------------------
   Climate Control Unit
Rebuilt : Fahrenheit
Push-button Assembly
Calibrated in Fahrenheit.    Year: 1988-
----------------------------------------
    Climate Control Unit
Rebuilt : Celsius
Push-button Assembly
Calibrated in Celsius.    Year: 1988-
------------------------------------------------
   Climate Control Unit
New : Celsius
Push-button Assembly
Calibrated in Celsius.    Year: 1988-

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=merc...