Troubleshooting - BMW K 1200 LT 1999 Repair Manual

Troubleshooting

Coolant overheat warning light comes on.
Check coolant in expansion tank. Is coolant
level too low?
no
Check thermostat. Thermostat does not open.
Is the left radiator warmer than the right one,
and the coolant pipe to the water pump hot?
no
Test the water pump. Is water pump faulty?
Fan motor does not cut in.
Check fuses. Fuse blown?
no
Check fan relay. Fan relay defective?
no
Check electrical circuit. Poor contact/open cir-
cuit?
no
Check fan motor. Fan motor defective?
no
Check thermostat. Thermostat does not open.
Is the left radiator warmer than the right one,
and the coolant pipe to the water pump hot?
17.12
yes
Add coolant.
yes
Replace thermostat.
yes
Repair/replace water pump.
yes
Replace fuse.
yes
Replace fan relay.
yes
Make good contact/eliminate open circuit.
yes
Repair/replace fan motor.
yes
Replace thermostat.