Normal Ventilation In Regulating Mode Function Test

WARNING: This page is about a different car, the 2000 Mercedes-Benz C43, 2000 Mercedes-Benz C280, 1999 Mercedes-Benz C43, and 1999 Mercedes-Benz C280. However, it is still accessible from the selected car via links, so may be relevant.

Adjust selector wheel to White range. Verify "EC" (economy) button light in A/C push button control module is off. Adjust air distribution knob to 4-o'clock position. If operation is correct, air will vent from lower and upper outlets. A/C compressor should be engaged. Air from center air vent will be tempered. Left and right duovalves will cycle. Coolant circulation pump will run. If this mode does not operate properly, perform the following tests:

DTC B1419: A/C COMPRESSOR CLUTCH under DIAGNOSTIC TESTS.
DTC B1416: COOLANT CIRCULATION PUMP under DIAGNOSTIC TESTS.
DTC B1417: LEFT-SIDE WATER (HEATER) VALVE under DIAGNOSTIC TESTS.
DTC B1418: RIGHT-SIDE WATER (HEATER) VALVE under DIAGNOSTIC TESTS.
BLOWER REGULATOR CONTROL in MISCELLANEOUS ELECTRICAL TESTS under SYSTEM TESTS.
DTC B1454: FRESH/RECIRCULATE SWITCHOVER VALVE under DIAGNOSTIC TESTS.
DTC B1422: SERIAL INTERFACE (K1) under DIAGNOSTIC TESTS.