Webasto
Malfunctions and troubleshooting | 5
9039398A_WSM_eThermo_Top_Eco_EN
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5.2
Table of causes of fault
Symptom
Possible cause
Corrective measures
Heater not responding, compon-
ent (coolant pump, vehicle fan)
not starting up.
n
230 V power supply not
connected
n
230 V cable connection not
present
n
Heater faulty
n
Wiring harness faulty
n
Fuse blown.
n
230 V power supply – check that the power cable is
connected correctly and supplied by the 230 V domestic
power grid; check domestic fuses if necessary.
n
230 V cable connection – check cable and connections
n
Heater – check wiring connections, replace heater if ne-
cessary
n
Wiring harness – check connections, check fuse and re-
place if necessary.
Coolant pump not running, heater
and vehicle fan working.
n
Coolant pump defective
n
Wiring harness faulty
n
Fuse blown.
n
Coolant pump – check wiring connection, check opera-
tion and replace if necessary
n
Heater – check wiring connections, replace heater if ne-
cessary
n
Wiring harness – check connections, check fuse and re-
place if necessary.
Coolant pump and vehicle fan not
starting up, heater heats up.
n
230 V supply voltage too
low
n
Wiring harness faulty
n
Fuse blown
n
Heater faulty
n
230 V power supply – check that the power cable is
connected correctly
n
230 V cable connection – check cable and connections
n
Heater – check wiring connections, replace heater if ne-
cessary
n
Wiring harness – check connections, check fuse and re-
place if necessary.
Vehicle fan not running, heater
and coolant pump working.
n
Wiring harness faulty
n
Fuse blown
n
Wiring harness – check connections
n
Check fuse and replace if necessary.
Heater not responding, all com-
ponents (coolant pump, vehicle
fan) running.
n
Heater faulty
n
Fuse blown.
n
Check fuse and replace if necessary.
n
Check heater – replace heater if necessary
Heater not starting, coolant pump
and vehicle fan starting up briefly.
Charge state of vehicle battery
very low.
n
Charge battery
n
Select lower fan speed.
