my 78 cd heater doesnt blow any hot air any ideas why

Servo failure is one of the primary causes.

MTU, do you know how to check to see if that's the problem? My heater won't blow any air unless the temp selector is clicked all the way to cold (and thusly not blowing hot air).

Does the 78 CD have a mono valve? If so, the diaphram inside the plunger may be bad. They can be replaced.

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the sooner you start... the sooner you'll get done If it ain't broke, don't fix it.. Its always simpler to tell the truth...
2007 Honda Accord EX
2007 Honda Accord SE V6
96 C220
97 Explorer - Found Another Home
2000 Honda Accord V6 - Found Another Home
85 300D - Found Another Home
84 300D - Found Another Home
80 300TD - Found Another Home
Previous cars:
96 Caravan
87 Camry
84 Cressida
82 Vanagon
80 Fiesta
78 Nova
Ford Cortina
Opel Kadet
68 Kombi
Contessa

Does your fan come on at all at any setting?

__________________
the sooner you start... the sooner you'll get done If it ain't broke, don't fix it.. Its always simpler to tell the truth...
2007 Honda Accord EX
2007 Honda Accord SE V6
96 C220
97 Explorer - Found Another Home
2000 Honda Accord V6 - Found Another Home
85 300D - Found Another Home
84 300D - Found Another Home
80 300TD - Found Another Home
Previous cars:
96 Caravan
87 Camry
84 Cressida
82 Vanagon
80 Fiesta
78 Nova
Ford Cortina
Opel Kadet
68 Kombi
Contessa

yup. When I have the temp selector all the way clicked on cold, the fan blows on low/auto/high on the right two climate switches (the two to the left of "off")

Is your engine temp up to normal?
My coupe will not even run the fan
until it is warmed up.
Defrost is the exception

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82 Mercedes 300CD 252k......slow ride

82 mercedes 300 SD...mi Unknown
83 Mercedes 300D ????ksniff..gone too
84 Mercedes 300D 148k........SOLD
85 Mercedes 300TD 386k and holding some one elses project