Were talking about a 85 300DT. Seems like I can only get either cold or hot air out of the vents, there is no in between. Any ideas??

diesel85,

Help us by giving us some examples of what you are trying when it is hot and also when it is cold. What buttons are you using, and is the heater fan operable and if so, always?? Is the cold due to good operation of the A/C or just ambient air entering the cabin?

This should help get some answers.

__________________
1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150

This same problem was just discussed here on the forum for a similar car. 300D heater is either off or full blast?

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970