I'm in the process of repairing my heater blower,i have narrowed my problem down to the regulator,sorry to say a new regulator is quite expensive.it seems as though it all pinpoints to the switch that attaches to the porcupine.it is a switch with the numbers 30057.does anyone know where i can get this relay or switch,and i can just resolder the wires to the new one.

 

I have taken my 300SDL apart and I am not sure about the other models. The blower regulator is a complex electronic circuit. It is a 3 pins device, 1 to ground, 1 to 12V and one is the regulation pin which controls the speed of the motor by varying the voltage. You should be able to tell whether the part works by removing the plug, measure the voltage of the regulating pin in the plug by setting the fan speed to Hi an Lo. The voltage should vary.

You may be able to get a replacement one from a junk yard.

 

I just lost the blower motor on my 87 300sdl. Any suggestions on replacement would be appreciated. Thanks, bob

 

Check the fuse. It is special fuse next to the main fuse box in a small black box. It is a flat fuse.

If it checks out OK then it is probably the motor or the regulator. You should be able to pull one from a junk yard. Follow the procedure in my last post to determine whether it is the blower itself or the electronics.