Operation CHARM: Car repair manuals for everyone.
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

In-Car Sensor

In-Car Sensor Terminal Location:





In-Car Sensor Testing:




Check the sensor resistance.

NOTE: If there is an open circuit in the sensor, the system will operate at maximum heating.
Conversely, if there is a short in the system, it will operate at maximum cooling.