TROUBLE DIAGNOSES — Electrical Components Inspection — Fan switch / Blower motor / Blower resistor

HA-83prose procedureUnverified

Fan-switch matrix: terminals 23 and 28 are the bus / common rails (closed for all positions 1–4); 27/26/25/24 are the per-speed pulls. OFF column intentionally empty.

Continued from HA-82

Electrical Components Inspection

FAN SWITCH

Fan switch — continuity check

1
Check continuity between terminals at each switch position.

Fan switch — terminal continuity per lever position

Terminal	1	2	3	4
24				○
25			○	○
26		○	○
27	○	○
23	○	○	○	○
28	○	○	○	○

OFF

4○

OFF

3○

4○

OFF

2○

3○

OFF

1○

2○

OFF

1○

2○

3○

4○

OFF

1○

2○

3○

4○

NOTE

Each ○ marks a terminal that conducts to the common bus at the indicated lever position. Read columns top-to-bottom: at fan-speed 4 the contacts close on terminals 24, 25 and the common (23, 28); at speed 1 the contacts close on terminal 27 only.

BLOWER MOTOR

Blower motor — mechanical inspection

1
Confirm smooth rotation of the blower motor.
2
Ensure that there are no foreign particles inside the intake unit.

BLOWER RESISTOR

Blower resistor — continuity check

1
Check continuity between terminals.

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