DTC Troubleshooting: B121B (H and A/C ON)
Turn the ignition switch to ON (II), and measure the voltage between heater control unit connector B (12P) No. 12 terminal and body ground.
Is there about 5 V?
YES
-
Go to
Step 20
.
NO
-
Check for a loose wire or poor connection at heater control unit connector B (12P). If the connection is good, substitute a known-good heater control unit and recheck. If the symptom/indication goes away, replace the original heater control unit .■