Heated Seats, Testing
Heated Seats, Testing
NOTE: If the voltage measured by the operating and display module, Climatronic Control Module J255 at terminal "30" drops below 12.3 V, the seat heating power is reduced, thus relieving the load on the Generator (GEN) (the electronic system of the operating and display module, Climatronic Control Module J255 reduces the activation duty cycle from 100% to 90 to 10% event if the specified seat temperature has not yet been reached).
Checking temperature sensors
Special tools and equipment
- Test Box V.A.G 1598A as well as corresponding Adapter V.A.G 1598/11 and Adapter -16 Terminals V.A.G 1598/12
- Diagnostic Operation System VAS 5051 A (with Multimeter Leads VAS 5051/7)
- Connector Test Set V.A.G 1594C
- Switch off ignition.
- Remove operating and display module, Climatronic Control Module J255.
- Connect Test Box V.A.G 1598A with corresponding Adapter V.A.G 1598/11 to connector - C -. Wiring and Component Check Using Test Box V.A.G 1598 A
- Connect Adapter -16 Terminals V.A.G 1598/12 to connector - D - (use second Test Box V.A.G 1598A or connect measuring instrument with suitable test lead from Connector Test Set V.A.G 1594C directly to Adapter -16 Terminals V.A.G 1598/12 ). Wiring and Component Check Using Test Box V.A.G 1598 A
NOTE: The terminal assignment of the connector - C-for the Adapter V.A. G 1598/11 and the connector - D -for the Adapter -16 Terminals V.A. G 1598/12 is identical to the assignment of the sockets at the Test Box V.A.G 1598A.
- Measure resistance between contact "5" in connector - C - (to Drivers Heated Seat Temperature Sensor G59 ) and contact "16" in connector - D - (Ground (GND) connection) at test boxes.
- Specified value: Resistance greater than 1.5 kOhms (kilo-ohms) and less than 25 k ohms (depending on temperature of temperature sensor; at a seat temperature of 20 degrees C, measured value is approx. 10 k ohms)
- Measure resistance between contact "6" in connector - C - (to Front Passengers Heated Seat Temperature Sensor G60 ) and contact "16" in connector - D - (Ground (GND) connection) at test boxes.
- Specified value: Resistance greater than 1.5 kOhms (kilo-ohms) and less than 25 k ohms (depending on temperature of temperature sensor; at a seat temperature of 20 degrees C, measured value is approx. 10 kOhms)
NOTE: The resistance of the temperature sensors in the seat heater elements changes with temperature (the values given in the table below are approximate).
Temperature at seat temperature Resistance of temperature
sensor in degree C sensor in kOhms
20 10
30 6.0
40 4.2
50 2.8
60 1.7
- If the resistance value is too high, check wiring to seat heater elements for open circuit or contact resistance and eliminate this. If the open circuit is in the seat, repair the seat.
Checking heating elements
Special tools and equipment
- Diagnostic Operation System VAS 5051 A (with Inductive Pickup (50 Amp) VAS 5051/9 )
- Connector Test Set V.A.G 1594C
- Test Box V.A.G 1598A and Adapter-16 Terminals V.A.G 1598/12
NOTE: All fuses OK
- Switch off ignition.
- Remove operating and display module, Climatronic Control Module J255.
- Disconnect connectors - D - and - F - from operating and display module, Climatronic Control Module J255.
- Connect test box Adapter -16 Terminals V.A.G 1598/12 to disconnected connector - D -.
- Connect Test Box V.A. G 1598A to Adapter - 16 Terminals V.A. G 1598/12
- Measure voltage between contact "3" at connector - F - and socket "13" (Ground (GND) connection) of Test Box V.A.G 1598A.
- Specified value: approx. Battery voltage
- Measure resistance between contact "1" at connector - F - (to heater element for Drivers Seat Heating Element Z6 ) and socket "13" (Ground (GND) connection) of Test Box V.A.G 1598A.
- Specified value: Resistance approx. 1.5 (to 2.5) to 25 ohms
- Measure resistance between contact "2" at connector - F - (to heater element in front passenger seat) and socket "13" (Ground (GND) connection) of Test Box V.A.G 1598A.
- Specified value: Resistance approx. 1.5 (to 2.5) to 25 Ohms
NOTE:
- Contact resistance at the various connectors may result in resistance values of up to approx. 25 ohms being measured. As soon as a voltage of 12 Vis applied, this contact resistance decreases and the seat heating function is not impaired.
- On right-hand drive vehicles, the driver seat is connected to contact "2" and the front passenger seat to contact "1".
- The resistance of the seat heater elements changes with temperature (at a seat temperature of 20 degrees C, the resistance is approx. 1.9 ohms).
- As resistances of less than 10 ohms cannot be measured with sufficient accuracy using workshop equipment, it is not possible to establish a short circuit in the wiring or in the seat heater elements.
- If the resistance value is too high, check wiring to seat heater elements for open circuit and eliminate this. If the open circuit is in the seat, repair the seat
- Plug connectors - D - and - F - to operating and display module, Climatronic Control Module J255 (all connectors are now plugged in at operating and display module, Climatronic Control Module J255 ).
- Guide wire to connector - F - contact "1" through Inductive Pickup (50 Amp) VAS 5051/9.
- On Diagnostic Operation System VAS 5051 A , set "Multi-meter measurement: inductive pickup (50 amp)" mode.
- Set both thumb wheels for heated seats (at operating and display module, Climatronic Control Module J255 ) to position "0".
NOTE: All connectors must be plugged in at the operating and display module, Climatronic Control Module J255.
- Start engine.
- Set thumb wheel for heated driver seat to position "6".
- Specified value: Display switches from approx. 0 A to less than 10 A
- Set thumb wheel for heated driver seat to position "0".
- Specified value: Display switches from less than 10 A to approx. 0 A
- Guide wire to connector - F - contact "2" (contact "1" on right-hand drive vehicles) through Inductive Pickup (50 Amp) VAS 5051/9.
- Set thumb wheel for heated front passenger seat to position "6".
- Specified value: Display switches from approx. 0 A to less than 10 A
- Set thumb wheel for heated front passenger seat to position "0".
- Specified value: Display switches from less than 10 A to approx. 0 A
NOTE:
- Interference on the current probe measuring leads 1 2 may cause a slight current to be displayed with the seat heating switched off.
- In the event of an open circuit or a short circuit in the connection to the seat temperature sensor, the output to the heater element is does not switch by the operating and display module, Climatronic Control Module J255.
- In the event of a short to Ground (GND) in the seat heater element or in the wiring, the operating and display module, Climatronic Control Module J255 does not switch on the heating (immediate deactivation as soon as current is too high).
- The design of the seat heater elements differs. Depending on heater element design there is thus a possibility of the two side bolsters being constantly heated, e.g. in the event of an open circuit in the seat cushion heater element (the temperature sensor is located in the seat cushion).