a/c melts fuse only on auto/high speed fan
 

1st-My 1992 300d melted the 30a fuse.Driving along and just went out.The a/c was on and the fan setting was set to Auto.I wired in a 30a auto reset breaker and the system performs fine on low speed without tripping the breaker.However, if I set the fan to auto/high it will trip within 3 minutes.
2nd The a/c still cools well set at 65 but will not cool if control temp is set above 68-70
Has anyone had either of these problems. Any help is appreciated.
Thanks Gregg

Check the amp's draw. On high, you'll find that draw is very close to fuse rating.
Bearing begining to sieze and/or brushes worn.
Sounds like new blower fan needed.

Check the current to the compressor clutch. I have seen these things do a partial short and draw a lot of current. I think the normal current draw is between 3-4 amps.

If it's easy to get to the blower motor, check if there's axial play in the main shaft. The bearings could be worn causing undue load.

Sixto
... stay tuned