Operation CHARM: Car repair manuals for everyone.
Home >> Mercury >> 2007 >> Milan FWD L4-2.3L VIN Z >> Repair and Diagnosis >> Windows and Glass >> Windows >> Testing and Inspection >> Pinpoint Tests >> Test K: The Defrost System Will Not Shut Off Automatically
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

Test K: The Defrost System Will Not Shut Off Automatically

PINPOINT TEST K: THE DEFROST SYSTEM WILL NOT SHUT OFF AUTOMATICALLY


K1-K2:






Normal Operation
The heated backlight relay, which is integral to the smart junction box (SJB), receives power from circuit SBB06 (BN/RD). When the rear window defrost switch is pressed on the electronic automatic temperature control (EATC) or electronic manual temperature control module (EMTC) control unit, a message is sent to the SJB through circuit CH122 (WH/OG). Once the SJB receives the message to turn on the rear window defrost, the SJB grounds the heated backlight relay coil, which sends power through the antenna module to the rear window defrost grid through circuit CLS38 (VT/WH).

Possible Causes
- Circuit CLS38 (VT/WH) shorted to power
- Antenna module
- Inoperative SJB
pro multis · About Operation CHARM