Ghost Blower Motor Operation
 

I have been having an odd problem with my 88 300SE. The AC system is charged, the compressor works fine and kicks in when I turn on the air conditioning but the blower motor either turns out and works great or does not at all. Any ideas on what causes this?

You may have a strip fuse by the fuse box. Check the strip fuse.

Check the three-prong fan plug where it plugs in at the firewall for corrosion.

The brushes in the motor my be wo' out.

The strip fuse is fine however, I did make an observation. The climate control will power on the blower motor when the ignition is in the run position but the vehicle is not running. The part that puzzles me even more is that it just blows full blast only through the front defrost vents when this occurs.:confused:

Blowing thru the defrost vents is the default. There is no vacuum when the car is not running to open any other vents.

If the blower will ONLY run on high speed, would that not implicate the push button unit?