AD83.70-W-6000-46C | AHE test of electrical system combustion air blower |
| Scope of test | Measuring instrument/ Test connection | Operation/Requirement | Specified value | Possible cause/Remedy | ||
1.0 | Combustion air blower Actuation |
B11 | Z13 |
B12 | Ignition: OFF Heater unit:OFF Disconnect 13-pin connection plug B on control unit (Z13), Connect cable bridge. | If burner motor not running: 1.1 If burner motor running: 1.3 | |
1.1 | Combustion air blower Internal resistance |
12/3 | Heater unit |
12/4 | Ignition: OFF Heater unit: OFF Allow engine and heater unit to cool down if necessary. Remove cover in front right wheel housing. Disconnect plug connection on heater unit. Carry out measurement directly on 12-pin plug on heater unit. | 15–30 Ω (at approx. | Value in order: Actuate burner motor directly (24V). If motor runs 1.2 Value > 30 kΩ: Actuate burner motor directly (24V). If motor does not run Replace motor. |
1.2 | Combustion air blower Preresistor |
12/6 | Heater unit |
12/5 | Ignition: OFF Heater unit: OFF Carry out measurement directly on 12-pin plug on heater unit. | 20–35 Ω | Value in order: 1.3 Value > 30 kΩ: Replace preresistor. |
1.3 | Combustion air blower Control unit, Cabling |
A12 () | Z13 |
B11 | Ignition: OFF Heater unit: OFF Remove cable bridge on control unit. Connect 13-pin connection plug B on control unit (Z13). Connect measuring instrument on control unit (behind timer) and ground. Heater unit: ON | Value 22.5-29.5 V: Replace relay K2 on trial if necessary. Heat heater unit up to coolant temperature of 85 °C (test run). If fault codes re-appear 1.5 Value < 1 V: 1.4 | |
1.4 | Combustion air blower Control unit, Cabling |
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| Z13 B12 | Ignition: OFF Heater unit: OFF Connect measuring instrument on control unit and ground. Heater unit: ON | Value 22.5-29.5 V: Replace control unit (Z13) on trial. Value < 1 V: Fuse F6-A5 Supply cable / plug connections | |
1.5 | Combustion air blower Cabling |
10/2 | K |
10/6 | Ignition: OFF Heater unit: OFF Re-connect plug connection on heater unit. Carry out measurement directly on 10-pin plug connection K on heater unit mount. | 30–50 Ω | Value in order: 1.6 Value > 30 kΩ: Cable from unit mount to heater unit (open-circuit). Plug connection FF8, pin 14/6 under electrical compartment and in air recirculation box pin 14/6. |
1.6 | Combustion air blower Cabling |
10/2 | K |
10/5 | Ignition: OFF Heater unit:OFF Carry out measurement directly on 10-pin plug connection K on heater unit mount. | Value > 30 kΩ: Cable from unit mount to heater unit (open-circuit). Value < 50 Ω: Ground connection on connection plug from heater unit. | |