Operation CHARM: Car repair manuals for everyone.
Home >> Lincoln >> 2008 >> Navigator 2WD V8-5.4L >> Repair and Diagnosis >> Windows and Glass >> Windows >> Testing and Inspection >> Pinpoint Tests >> Test I: The Defrost System Is Inoperative
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 I: The Defrost System Is Inoperative

PINPOINT TEST I: THE DEFROST SYSTEM IS INOPERATIVE

Normal Operation
During normal operation, the heating ventilation air conditioning (HVAC) module - electronic automatic temperature control (EATC) module or HVAC module - electronic manual temperature control (EMTC) activates the rear window defrost relay by grounding the relay coil through circuit CH122 (WH/OG). When the defrost relay is activated, power is supplied from the relay to the rear window defrost grid through circuit CRD06 (BN/YE) and also to the LH/RH exterior rear view mirror heaters through circuit CBB23 (BN/YE). Ground is supplied to the rear window defrost grid and exterior mirror heaters through circuit GD150 (BK/WH).

This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Rear window defrost relay
- Wiring, terminals or connectors
- HVAC module - EATC
- HVAC module - EMTC
- Open or short in rear window defrost grid


I1-I3:






I3 Continued:






I4-I5:






I5-I6:




pro multis · About Operation CHARM