374116 - O22 FRONT PASSENGER SEAT HEATING NOT WORKING

the front passenger seat heater pad and potentiometer are connected to a control module located under the seatThe seat heater pad consists of two elements, fitted in the seat and in the backrest, controlled in parallel by the control moduleThe heater pad in the seat has an NTC sensor for controlling the temperature.
STEPOPERATIONS TO BE CARRIED OUTTEST RESULTS
1ELECTRICAL SYSTEM CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Remove the seat from the fastening points maintaining the electrical connections.Check for a supply positive and earth at the control module connector. (Wiring Diagram ) E3075 HEATED SEATS Move on to Step 1. no positiveMove on to Step
2. no earthMove on to Step
2ELECTRICAL SYSTEM CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check:

  • the continuity/insulation of the supply lead between the control module and the passenger seat coupling
  • the continuity of the earth lead between the passenger side control module and the passenger seat coupling
  • the continuity of the earth lead from the passenger seat coupling to the passenger side dashboard earth (Wiring Diagram ) E3075 HEATED SEATS
  • the continuity/insulation of the supply lead from the passenger seat coupling to the luggage compartment junction unit.
Move on to Step Electrical equipment faultyRestore the electrical connection. (Wiring Diagram ) E3075 HEATED SEATS
3ELECTRICAL SYSTEM CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Electrically disconnect the seat, remove the control panel and check the electrical connection between the temperature selector and the control module (Wiring Diagram ) E3075 HEATED SEATS Move on to Step Electrical equipment faultyRestore the electrical connection (Wiring Diagram ) E3075 HEATED SEATS
4COMPONENT CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check the operation of the temperature selectorMove on to Step Temperature selector brokenReplace the temperature selector
5ELECTRICAL SYSTEM CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check the electrical connection between

  • Control module and seat heater pad
  • Control module and seat heater pad sensor
  • Control module and backrest heater pad
  • Heater pads and earth (Wiring Diagram ) E3075 HEATED SEATS
Move on to Step Electrical equipment faultyRestore the electrical connection (Wiring Diagram ) E3075 HEATED SEATS
6COMPONENT CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Check

  • the resistance of the heater pads (about 5.5 ohm at 20 degrees)
  • the resistance of the heater pad sensor (about 1kohm at 20 degrees)
Move on to Step 1. Heater pads broken1. Replace the heater pads
2. Sensor broken2. Replace the seat heater pad.
7CHECK ON CORRECT OPERATIONALL OKPROBLEMS ENCOUNTEREDACTION
Check that the fault is no longer presentFault persistsReplace the control module