Workshop Manuals Factory service & repair Alfa Romeo
Alfa Romeo 155 Factory Service Manual (1992-1998)42 · Electrical 26 – Heating, ventilation and air conditioning
42 · Heating & A/C

Test h

Make
Alfa Romeo
Model
155 Factory Service Manual
Year
1992–1998
Section
Check speedometer signal › Test h
Electrical 26 – Heating, ventilation and air conditioningTest h
TEST PROCEDURE RESULT CORRECTIVE ACTION
G5 CHECK CONTINUITY
- Check continuity between pin A1 of Q31 and pin C6 of control unit Q21a		 OK Carry out step G6
NOT OK Restore wiring between pin A1 of Q31 and pin C6 of control unit Q21a (PNK)
G6 CHECK CONTINUITY
- Check continuity between pin A2 of Q31 and pin B3 of control unit Q21a		 OK Check and if necessary replace control unit Q21a
NOT OK Restore wiring between pin A2 of Q31 and pin B3 of control unit Q21a (GRY-GRN)
G7 SELF-DIAGNOSIS (SHORT CIRCUIT CHECK)
- Disconnect the regulator Q31: "0" displayed		 OK Replace the regulator Q31
NOT OK ("FF" displayed) Carry out step G8
G8 CHECK VOLTAGE
- Check for voltage (0V) between pins A1 and A2 of regulator Q31		 OK Check and if necessary replace control unit Q21a
NOT OK Restore wiring between:
• pin A2 of Q31 and pin B3 of control unit Q21a (GRY-GRN)
• pin A1 of Q31 and pin C6 of control unit Q21a (PNK)

TEST H

NOTE: If the no part of the conditioner is working, first refer to test A; if it is only the fan which is not working, carry out the following test H.

CHECK ELECTRIC FAN WITH RELATIVE SPEED REGULATOR

TEST H

TEST PROCEDURE RESULT CORRECTIVE ACTION
H1 CHECK FUSE
- Check for damage of fuse F13 in fusebox G1		 OK Carry out step H2
NOT OK Replace the fuse (20A)
H2 CHECK FUSE
- Check for damage of wander fuse Q43		 OK Carry out step H3
NOT OK Replace the fuse (50 A)

(continues)

Parts & tools for this job For 1992 Alfa Romeo 155

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