Economy Not In Heating Mode Function Test

WARNING: This page is about a different car, the 2001 Mercedes-Benz SL500 and 2000 Mercedes-Benz SL500. However, it is still accessible from the selected car via links, so may be relevant.

Set temperature to LO. Press EC button and select face vent mode. If this mode is operating properly, ambient temperature air will flow from center outlets and A/C compressor will be off. If this mode does not operate properly, perform the following tests:

DTC B1417: AUTOMATIC A/C MONOVALVE under DIAGNOSTIC TESTS.
BLOWER REGULATOR CONTROL in MISCELLANEOUS ELECTRICAL TESTS under SYSTEM TESTS.
DTC B1419: A/C COMPRESSOR CLUTCH under DIAGNOSTIC TESTS.
VACUUM DISTRIBUTOR BLOCK, VACUUM RESERVOIR & SWITCHOVER VALVE BLOCK TESTS and VACUUM ACTUATOR CIRCUIT TEST in VACUUM TESTS under SYSTEM TESTS.