Climate-control diagnosis
Poor cooling can arise from refrigerant charge, compressor command, pressure sensing, condenser airflow or temperature-door control. Weak cabin airflow can result from filters, blower motor, regulator, ducts or flap operation. Confirm system pressures and temperatures using approved equipment; inspect blower current and actuator positions where relevant. Refrigerant recovery and charging must follow applicable regulations.
Repair decisions and verification
Measure vent temperatures and airflow at multiple settings and confirm no new control-system faults.
Vehicle context: C 300, 2013. Chassis: C-Class W204 4MATIC Sedan. The same warning may require a different diagnostic path on another engine or year.
Symptoms and customer complaints
A/C inoperative despite full refrigerant charge.
Blower intermittent after regulator replacement one week earlier.
Warm air/no cooling.
Intermittent blower operation.
Diagnostic approach
The researched cases used checks including Command clutch and check connector power; Check blower current draw. A technician must interpret the results in the context of the actual vehicle.
The recorded case findings included Good power, no clutch response; Excessive amperage. These findings are examples, not assumptions to apply to every Mercedes-Benz.
Documented causes in the source cases included Nonresponsive A/C compressor clutch/compressor; High-current blower motor. Similar symptoms can result from other faults, so testing is needed before repair.
Reported successful case repairs included Replaced compressor and drier; normal HVAC cooling restored; Replaced blower motor; fixed. These are external research outcomes, not work claimed by our shop.
If you are experiencing similar symptoms, call Mich’s Foreign Cars in Hickory at 828-324-6012 with the vehicle year, engine, warning message and the conditions under which the problem occurs.