Economy Setting Not In Heating 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 Blue range. Verify "EC" (economy) button light in A/C push button control module is on. Adjust air distribution knob to 9-o'clock position. If operation is correct, air venting from center vents will be ambient temperature. A/C compressor should not be engaged. If this mode does not operate properly, perform the following tests:

DTC B1419: A/C COMPRESSOR CLUTCH under DIAGNOSTIC TESTS.
DTC B1417: LEFT-SIDE WATER (HEATER) VALVE under DIAGNOSTIC TESTS.
DTC B1418: RIGHT-SIDE WATER (HEATER) VALVE under DIAGNOSTIC TESTS.