before you put it all together, you ought to remove the servo, flush the heater core, flush the servo and flush your radiator coolant. get all the gunk out.
esp flush the servo

in hopes that it is functional.
check your AC amp to see if it is not burnt.

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1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
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1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD