- Determine non-fuse protected components according to wiring diagram.
- Remove fuse 9 for overhead control panel control unit (N70) from rear signal acquisition and actuation module (SAM) (N10/2).
This ensures that the in-car temperature sensor fan motor (N70m1) is not supplied with power.
Observe a run-on time of the control units of approx. 4 minutes.
- Read off total quiescent current on the digital multimeter and note value.
Digital multimeter
- Separate connector or connection at the possible quiescent current consumer and tie back to avoid inadvertent contact.
- Read off current total quiescent current on digital multimeter and note value.
If the total quiescent current reduces by more than 0.02 A (20 mA) after disconnecting a component, this component is defective. Defective components must be replaced.
- Connect coupling or connector with the component again.
- Repeat testing with all closed-circuit accessories as described.
- Add the noted differences.
This test step is carried out in the event that several unfused current paths have a slightly increased quiescent current consumption:
- If the sum of the differences ≤is 35 mA, then the unfused current paths are OK.
- If the sum of the differences is > 35 mA, then the components of the unfused current paths with the highest quiescent currents should be checked. It is unfortunately not possible to state any specifications in this case as these depend on the particular current path and on the calculated total current.
- To check, re-test quiescent current.