If a customer complains about the above problem, this could be caused by a defective temperature sensor at the evaporator. The defective temperature sensor causes the evaporator surface to freeze so that heat exchange is no longer possible. First, a plausibility test should be performed using the diagnostic tester. Under the "Parameters" menu item, you can usually compare the temperatures of the interior temperature sensor and the sensor on the evaporator, when the air conditioning is switched off. If the measurement shows significant differences (interior 20 °C and e vaporator 30 °C), this is already an indication of a faulty t emperature sensor on the evaporator. Then check the electrical connector of the sensor. Water ingress can cause corrosion of the connector contacts, which then leads to failure or malfunction. If this is the case, the contacts must be cleaned. If the contacts are badly damaged, the only remedy is to replace the temperature sensor.
Important safety notice
The following technical information and tips for practical use have been set up by HELLA in order to offer professional support to automotive workshops in their daily work. The information available here on this website is only to be used by appropriately trained specialist staff.
The reprinting, distribution, reproduction, exploitation in any form and disclosure of the contents of this document, even in part, is prohibited without our express written approval and indication of the source. The schematic illustrations, figures and descriptions are for explanation and presentation of the document text and cannot be used as a basis for installation or design. All rights reserved.
Not helpful at all
Very helpful