560 SL Heater/AC Fan

[Tom McMenamin]

I am not sure of the problem here!

Let me try to express what's going on and maybe I can get the help I need.

The Fan on my air conditioning seems to cool the car but not overly so. It seems that it is always on low. The air doesn't roar out of the vents as on most cars . I realize that German cars are notorious for weak A/C but this is just not right.

Now when you go to Parts Shop there are 2 things for replacement: 1) the entire fan and motor assembly and 2) a Fan Control relay.

Question: How do you tell which you need?

As a DIY and not a good one at that my tendency is to pull the entire assembly and replace it and go from there. As I have learned you maybe should not do that. Sometimes the new stuff doesn't do as well as the old. Repairs sometimes are better than replacement.

Any help greatly appreciated!

[stevebfl]

The fan is easy to access under the black plastic cover, center rear of engine compartment.

I don't remember where the resister pack is by if you can get to the two wires that power the motor verify that they have battery voltage across them.

In other words the motor runs in high speed with battery voltage across the two terminals of the motor. Reduced speeds are achieved by adding resisters such that the motor only gets 6v or 8v or 10v say. measure the voltage, or power it up with a jumper to 12v (only do this with the motor mounted as it will take off in high speed.)

If the motor gets 12v (battery voltage) and is slow then it is bad. If the motor never gets more than 6 or 8v then the control of blower speeds is faulty and that diagnosis will require a wiring diagram.