16 · Diagnostics

O20 Front seat heating not working

Fault diagnosisO20 Front seat heating not working

With the ignition on, when the appropriate button on the front seats is pressed, the heating function does not come on.

NOTA: Device operation is automatically cut out at a certain temperature by a thermal contact inside the device.

Step	Test procedure	Result	Action
0	PRELIMINARY CHECKS When the button on the seat is pressed, check that the led on the button comes on to indicate that the function has been activated.	OK	Move onto step 1
0		Led comes on	Move onto step 3
1	CHECKING SEAT HEATING ELECTRICAL CIRCUIT Check, in order: seat heating fuse services relay operation of the switch and led seat heating device power supply and earth Wiring diagram E3075 HEATED SEATS	OK	Move onto step 2
		Component defective	Replace the component involved (if a fuse is involved, search for the cause of the problem) End of diagnosis
		Connections not correct	Restore the connections End of diagnosis
2	CHECKING SEAT HEATING DEVICE Check, in order: condition of thermal contact built into the device continuity of resistor connection condition of resistor filaments	OK	Move onto step 3
2		Connections not correct	Change the seat heating device End of diagnosis
3	CHECK CORRECT OPERATION Check that the fault is no longer present	OK	End of diagnosis
3		Fault persists	Incorrect selection of diagnostic procedure

Parts & tools for this job Staging For 1997 Alfa Romeo 156

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