Air conditioner fault tables

Air conditioner fault tables

10000165-en

Blower malfunctions

Malfunction Cause Remedialaction

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Blower not working Fuse defective or loose Check fuse contact, if necessary, plug in correctly. Replace defective fuse. Reappearance of the defect after a short time indicates a short-circuit. Check blower for blocking or other defects and rectify. Loose connector Check that connector at the side of the unit is firmly in place. Plug in properly, if necessary. Check connections at blower switch. Open the unit and check electrical connections inside.

Blower cannot be stopped Blower performance reduced Connecting cable damaged or ripped off Replace cable, observing correct cable run and connection.

Wrong electrical connections

Check connecting cables and, if necessary, reconnect properly. Blower switch defective Replace by new OEM part. Blower assembly blocked Eliminate cause of blockage, e.g. by removing foreign object from rotor. If necessary, install new blower. Blower motor defective Replace blower. Blower switch defective Replace blower switch.

Wrong nominal supply voltage

Nominal voltage of conditioner and of vehicle system must be identical. Replace blower. Contacts dirty Clean connector contacts. Work carefully to avoid shortcircuits.

Heat exchanger heavily contaminated

Blower ducts obstructed Clean carefully to avoid any damage resulting in consequential leaks. Check air ducts and outlets for obstructions and remove any foreign objects.

Insufficient cooling performance

Malfunction Cause Remedialaction

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Compressor not working Open circuit in compressor solenoid Check power supply to the clutch.

Thermostat defective Replace thermostat. V-belt loose or broken Adjust belt tension, replace belt. Belt pulley not turning although magnetic clutch is engaged Check compressor and replace, if necessary.

Compressor clutch slipping Repair clutch or replace compressor.

Evaporator flooded Expansion valve jammed or stuck in open position Replace expansion valve (block valve).

Evaporator frozen up Thermostat sensor in wrong position Install sensor in another place.

Evaporator clogged up Cooling fins dirty Clean evaporator. Loss of refrigerant Refrigerant line defective Check all lines for discontinuities caused by external influences or chafing. Leaks in the system Evacuate the system, refill, check for leaks and repair.

Filter mat (recirculated air) Air filter element (fresh air) Filter mat clogged up Clean or replace filter mat.

Air filter element clogged up Clean or replace air filter element. See also: “Heating, cleaning the fiilter element“.

Heating is on Bowden cable wrongly centered or defective Adjust Bowden cable (see: "Heater valve, adjusting the Bowden cable") or replace.

Insufficient heating performance

Malfunction Cause Remedialaction

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Heating not working Cooling agent still cold Waituntil the engine has reached its operating temperature. Water valve closed Open the heater valve (see Operator's Manual: "Ventilation and heating").

Water lines kinked or crushed Eliminate cause of the fault.

Heating working with reduced performance

Heating cannot be stopped

Air distribution flaps uncontrollable Heat exchanger, filter mat or air filter element (heating) heavily soiled Clean carefully to avoid any damage resulting in consequential leaks. When too heavily soiled, replace filter mat or air filter element.

Amount of water flowing through heat exchanger insufficient

Water lines crushed or kinked. Change position of hoses. Insufficient pressure of water pump (remedial action see above). Air in heat exchanger The radiator is self-venting when the pump pressure is high enough. Install an auxiliary or more powerful water pump.

Conditioning unit underdimensioned If necessary, install an additional heating or a more powerful conditioning unit.

Bowden cable controlling the water valve wrongly adjusted Readjust the Bowden cable.

Heater valve not installed correctly in flow and/or reflow line

Betätigung bzw. Bowdenzug defekt Check valve mounting position with respect to flow and reflow direction and correct if necessary. See also: "Air conditioner, inspection and servicing work“. Check control / Bowden cable and replace if necessary.

Flap hinges sluggish Check flap and lubricate, if necessary. Flap deformed Check flap. Flap blocked by foreign object Check flap and remove foreign object if necessary.

Conditioner very noisy

Malfunction Cause Remedialaction

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Conditioner very noisy V-belt loose or excessively worn Retension V-belt or replace.

Clutch noisy Repair clutch. Compressor supporting bracket loose or wornout parts inside the compressor Repair bracket, replace compressor.

Blower motor excessively worn Replace blower.

System overfilled Evacuate refrigerant until the high pressure reading is normal again (approved workshop).

Not enough refrigerant in the system Check for leaks, refill the system.

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