In an effort to get some more info, I have consolidated what I think is the important info from the prior thread in Vintage and thought I'd also post it here since it also falls into this category and I need as much help as I can get on this one. To see the entire thread (so far) go here: http://www.peachparts.com/shopforum/showthread.php?t=235411

Car is 19775 240D w115.
My blower/fan does not work properly.
When the fan speed selector (round switch between dash grill vents that says "defrost" and has 3 positions) is turned on with the heat on, no fan/no air at ANY of the speeds.
When the fan speed selector is turned on with the A/C turned on, no fan/no air on the first 2 speeds, but appropriate amount of air when turned to speed 3.

The change over switch (down above the go-pedal) works fine, when the A/C knob is turned on (this is the only time that the fan will blow, and only with the knob in position 3).

In reference to the relay on the firewall in the engine compartment aboeve the brake master cylinder: Imagine the four pin connector as such: pins connected to the following: red wire, green wire, green/black/yellow wire and green/black wire. I assume the red wire (lower left, like you said) is positive and the other green combinations are the grounds you mention above. When connected to a voltmeter, I get a power response across the rd to gn, rd to gn/bk/yw and rd to gn/bk when the defroster knob is in the 1 and 2 position, but when I put it in the 3 position, I only get a power response on the voltmeter at the rd to gn/bk/yw, the other 2 give no response.

Heater fan itself: I took off the wipers and cowling and spun/lubricated the fan, pretty easy to reach so I spun it alot in both directions and sprayed it up well, but no change.

Most recent occurrence: I noticed that the #6 fuse was blown. #6 is for the heater fan, nothing to do with the A/C fan. So I put in a new fuse and this is what happened: Heater fan only, defrost knob turned to: low=nothing, med=nothing, high=nothing. A/C switched on and defrost knob turned to: low=nothing, med=nothing, high=blows fuse #6, but runs A/C fan.

I appreciate any help and would like to know if there is anything left I can test and how to do it. I am not saying that it isn’t the heater motor, just that I want to make sure it is before I go to the trouble and expense (more the trouble from what I have read) of taking the dash apart. Thanks in advance, Alex

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"Frau Blue Car" 1980 240D think Frau Bluker, cue the horses, formerly known as "China" from JimmyL
"Gunther" 1982 300D.....Turbo!! A/C!! Sunroof!!
"Fraulein" 1975 240D----Donated to NPR