16 · Diagnostics

S55 Heater noisy' (in passenger compartment)

Fault diagnosisS55 Heater noisy' (in passenger compartment)

The heater is working properly, but there is excessive noise coming from the duct distributor assembly

Step	Test procedure	Result	Action
1	ELECTRIC FAN CHECK Check the climate control fan and ensure the following in particular: there are no foreign bodies inside the fan casing there are no vibrations at the various speeds (causing operation with the fan switched off, but the electrical connection engaged)	OK	Move onto step 2
		Fan dirty	Clean the fan casing and all the ducts End of diagnosis
		Electric motor noisy, fan unbalanced	Replace the electric fan Op. 5020A30 End of diagnosis
2	AIR DUCTS CHECK Check that the air ducts inside the dashboard and the vents are intact and that there are no foreign bodies which could cause noise	OK	Move onto step 3
2		Air ducts obstructed or damaged	Restore the operation of the ducts and the vents (see Assembly 5010B) End of diagnosis
3	DISTRIBUTOR DUCT CHECK Check whether there are foreign bodies or damaged parts inside the duct distributor assembly which could cause noise	OK	Move onto step 4
3		Air passages obstructed or damaged	Restore the operation of the distributor duct If necessary, replace one of the flapsOp. 5020A24 End of diagnosis
4	CHECK CORRECT OPERATION Check that the fault is no longer present	OK	End of diagnosis
4		Fault persists	Incorrect selection of diagnostic procedure

Parts & tools for this job For 1997 Alfa Romeo 156

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