Just purchased a 74 240d and the defrost fan stopped working (means no AC!). When you turn the switch you can feel the ac compressor pull on the motor, and you can feel cold air slightly from under the dash, but nothing else. Changed the fuse with no change. Thanks for any help!!!!

Defrost fan and A/C fans are separate animals. You do NOT want to replace the heater-defroster fan. Major PITA.

The A/C fan is a circulating squirrel cage type of fan located at the bottom of the center dash console. Look directly in front of the window switches and you will see a grill. The fan is located there. Double check the change-over switch mounted above the accelerator pedal. It's usually the culprit for the A/C fan not kicking on.

Thanks for getting back to me! I didn't get a manual with the car so I am still trying to figure out what is what on the dash. I called it the defrost switch because that is what it is labeled. I found that when I turn it (1 to 3 clicks), it caused the ac to blow out the vents. Now it doesn't. I will check the switch by the accelerator. Thanks again!!!

The switch is controlled by vacuum elements--there should be a brass or chrome lever that moves up and down above the accelerator pedal on the A/C housing--good luck


Tim Kraakevik
kraakevik@voyager.net
Four 114's, Four M110's

I found the lever by the gas pedal (diesel) but it didn't help. I notice I have vents below the radio which have a squirrel cage behind it, which I assume is the AC vents. But when the AC was working it was coming out the vents above the radio and controlled by the defrost fan, which now doesn't work. I think it is time for me to try and find an owners manual so I can figure out what is what on the dash. In the mean time there is a local shop recommended by the local MB Club in VB that I am going to take it by and have them take a look. Since I just got it I think it would be a good idea to have a pro do a once over. Thanks for the comments!!!!!!!!

Those are the air returns. The air does come from the mid-level vents.

Does anyone know where I can find an owners manual for a 74 MB 240D that doesn't cost and arm and a leg? Funny I can find them for every other year MB for $40 but my particular year it's over $100. Thanks!!!