AD83.70-W-6000-30B | AHE test of electrical system temperature sensor short to ground |
| Scope of test | Measuring instrument/ Test connection | Operation/Requirement | Specified value | Possible cause/Remedy | ||
1.0 | Water temperature sensor Cables, Internal resistance |
14/8 | G |
14/ 10 | Ignition: OFF Heater unit: OFF Open flap on air recirculation box. Disconnect 14-pin plug connection on vehicle blower. | 700–1300 Ω (at coolant temperature approx. 20 °C) | Value in order: 1.2 Value < 50 Ω: 1.1 |
1.1 | Water temperature sensor Internal resistance |
12/8 |
| Heater unit 12/ 10 | Ignition: OFF Heater unit: OFF Allow engine and heater unit to cool down if necessary. Remove cover in front right wheel housing and remove heater unit. Disconnect 12-pin plug connection on heater unit. | 700–1300 Ω (at coolant temperature approx. 20 °C) | Value in order: Cable / plug connection from air recirculation box to heater unit (short-circuit or short-circuit to ground). Value < 50 Ω: Replace water temperature sensor on trial. Collect draining coolant. |
1.2 | Water temperature sensor Cables, control unit |
A5 | Z13 |
A8 | Ignition: OFF Heater unit: OFF Re-connect plug connection G on vehicle blower. Disconnect 13-pin plug connection A on control unit. | 700–1300 Ω (at coolant temperature approx. 20 °C) | Value in order: Check whether sporadic short-circuit to ground is possible (chafed cable etc.). If no fault visible, replace control unit (Z13)on trial. Value < 5 Ω: Cable to heater unit (short-circuit to ground). Plug connection behind radio console or under electrical compartment (short-circuit to ground). |