1983 Mercedes Benz 300sd 6 cyl Two Wheel Drive Automatic 135000 miles
1983 MB 300SD, when you turn the heater controls on, by depressing any of the buttons on the control module, you hear a " hum" low sounding hum but nothing happens with heat. The blower motor works, I jumped it from the battery and it spins just fine. Anyone with any ideas about what the problem my be, I would be every so grateful. Many thanks.
You may have to remove the climate control panel and check all the vacuum lines and the wiring, these climate control unit are very hard to fix check your local junkyard I know there are a lot of them here in Utah full of old Mercedes for parts.