Just today, i had an ac problem with my 1993 Mercedes 400E. Hard to explain, but ill do my best and hopefully you guys can help me. A/C works when im driving at high speed and turn the switch to economy, econonmy pretty much brings the air outside inside along with the cold a/c. Now if i switch it to regular cycle a/c on cold there's no air. I figure either the blower motor is bad or speed control. I checked all of the fuses and they look good for the blower motor. I asked around and people say the blower motor hardly breaks down. I havent check the blower motor because im trying to find an easier and less expensive way why the a.c doesnt blow. I know the blower motor is behind the dashboard and underneath the windshield wiper. If anyone is or have experience this please let me know and how to solve my problem. Thank You!

 

Not real sure about your condition,First,Is there enough r134a in the system?
This might help
It is straight form my Mitchell On-Demand software CD's
chose your model and year and these are the results
Troubleshooting

• Blower does not operate correctly
• Blown fuse
• Blower motor windings open
• Resistors burned out
• Motor ground connections loose
• Harness connections loose
• Blower motor switch inoperative
• Blower relay inoperative
• Fan binding or foreign object in housing
• Fan blade broken or bent

Blower motor resistors located below power brake booster,Software does not say about the Blower relay.
Also noted during this year that provided by DaimlerChrysler.