Evening all.
This is my issue.
The heater blower doesnt always start.When it does,if I happen to hit a small pot hole on the road it will stop,as for the defrost mode (front) it doesnt fail much but when it does stop or does not restart all I have to do is press on the heat dial indicator for it to restart.
Could both of these issues be related?
What if I took apart the heater switch (press button)...Would I be able to repair anything? 1983 300SD

Best regards
Dan
Vancouver Canada

There can be cracked soldier joints on the circuit board where the relays mount. I remember a back circuit board attached at 90 degrees to the larger one. The joints can also crack there. DON'T use a high wattage solder gun.

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My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.

The blower problem might be worn brushes. If they are worn so far that the springs no longer hold them tight, they will sometimes fail to make contact and you will get the described symptoms. If the commutator is not also badly worn, you can solder in new brushes. Otherwise you'll have to replace the motor for about $100 (some suppliers have it less expensive, some charge more).

The climate control electronics could also be a problem, as Motorhead has said. Many people, including myself, have been successful in resoldering this assembly and returning the climate control system to full operation. There are a number of threads on the subject here, including some good photos, if you will do a search.

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"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

Is it difficult to remove the blower motor and the part of the console where the heater controles are?
I guess once this is done its pretty straight forward in regards to welding any loose wires...