Diagnosis of malfunctions of the heating system

Defective heater motor fuse

Check motor fuse, replace if necessary

Faulty heater motor switch, contacts corroded

Check for voltage at the heater motor motor. If not, remove the motor switch and check. Clean connections

Worn graphite motor brushes

Check for voltage at the motor contact with the ignition on and the switch on. If present, remove the motor, check, if necessary, replace the graphite brushes

Faulty preresistance

Replace connection board

Heating valve flexible cable damaged or misaligned

Adjust flexible cables or replace

Low coolant level

Check coolant level, top up if necessary

Faulty coolant thermostat

Check coolant thermostat, replace if necessary

Penetration of dirt, foliage

Remove motor and clean. Clean the duct

Fan wheel out of balance, defective bearing

Remove the motor and check for ease of movement