Suzuki 2000 Grand Vitara SQ625 Service Manual page 239

6-1-128 ENGINE (H25 ENGINE)
STEP
2 A/C ON Signal check:
(1) Check voltage between E61-27 and ground under
following conditions.
Engine running and A/C switch and/or heater
blower switch OFF 0 – 1.5 V
Ignition switch ON and both A/C switch and heater
blower switch ON 10 – 14 V
Are check results as specified?
ACTION YES
A/C signal circuit is
in good condition.
NO
Faulty "Gr/W", poor
performance of ECT
sensor, TP sensor,
inputted engine
start signal or faulty
A/C control module.
If none of the above
exists, substitute a
known-good ECM
(PCM) and recheck.