Operation CHARM: Car repair manuals for everyone.
Home >> Lexus >> 1993 >> ES 300 V6-3.0L (3VZ-FE) >> Repair and Diagnosis >> Heating and Air Conditioning >> Power Transistor HVAC >> Testing and Inspection
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Power Transistor HVAC: Testing and Inspection

Power Transistor Circuit
The air conditioning control assembly controls the blower speed by varying the voltage at terminal BLW which applies the base current to the power transistor.
The air conditioning control assembly also monitors the power transistor collector voltage at terminal, VM to control blower air volume precisely.

Diagnostic Chart:




Wiring Diagram:






Inspection Procedure - Step 1:




Step 2:




Step 3:




pro multis · About Operation CHARM