3308681 - L30 SUPPLEMENTARY HEATER WILL NOT COME ON

the heater only comes on when the engine is running, with engine water temperature <72° C and external air temperature <= 5° C.

		Results of the tests
1	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Connect diagnostic equipment (Examiner or other instruments) to the diagnostic socket. Check that there are no faults in the combustion control unit	Continue to Step 2	An error is detected in the control unit	Continue following the instructions for the diagnostic equipment
			Lack of dialogue with the control unit	Restore the connection between the combustion control unit and the diagnostic connector ( See   E6015  ADDITIONAL HEATER )
2	CHECK SUPPLY RELAY	All OK	Problems met	Operation
	With the ignition on (MAR), check that the combustion control unit supply relay is working	Continue to Step 3	Relay faulty	Replace the mixture motor Op.   5040D77
			Lack of continuity	Restore the connections ( See   E6015  ADDITIONAL HEATER )
3	CHECK THAT BOILER COMES ON	All OK	Problems met	Operation
	With the water temperature <72° C, bridge the external air sensor, start the engine and check that the boiler comes on	Continue to Step 4	Boiler does not come on	Restore the connections ( See   E6020  AIR CONDITIONING )
4	CHECK EXTERNAL AIR TEMPERATURE SENSOR	All OK	Problems met	Operation
	Check the operation of the outside air temperature sensor. See Test   5020MA  Check external air temperature sensor for the additional heater	Continue to Step 5	Sensor faulty	Replace sensor P Op.   5010D12
5	CHECK ALTERNATOR D+ SIGNAL	All OK	Problems met	Operation
	Check the presence of the alternator supply D+ signal	Continue to Step 6	Alternator signal interrupted	Restore the connections ( See   E6020  AIR CONDITIONING ), if necessary overhaul the alternator
6	CHECK FUEL PUMP	All OK	Problems met	Operation
	Check operation of fuel pump: See Test   5020MB  Check operation of pump dispensing/delivering fuel to supplementary stand-alone heater	Continue to Step 7	Fuel pump faulty	Replace additional fuel pump Op.   5020M30
			Connections not correct	Restore the connections ( See   E6020  AIR CONDITIONING )
7	CHECK AIR LEAKS	All OK	Problems met	Operation
	Check for incorrect intake of burnt air	Continue to Step 8	Boiler unit leaking	Repair the leak
			Faulty burner	Replace Vedere burner unit Op.   5020M14
			Faulty exhaust pipes	Restore correct operation
8	CHECK COMBUSTION AIR FAN	All OK	Problems met	Operation
	Check operation of combustion air fan: See Test   5020MD  Check supplementary stand-alone heater fuel air fan	Continue to Step 9	Overload and fan outlet command (i>500 mA) because of short circuit	Replace combustion control unit Op.   5020M14
			Fan fault	Replace combustion air fan Op.   5020M14
9	CHECK PLUG	All OK	Problems met	Operation
	Check operation of plug: See Test   5020MC  Check additional stand-alone heater plug	Continue to Step 10	Plug in A.C. or D.C.	Replace plug burner kit Op.   5020M14
10	HECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists	Search for the fault starting from another symptom'