Printed Rear Window Defogger

Repair Procedures

Inspection

Wrap the tip of the voltmeter probe with tin foil to avoid damaging the heater line. Press the tin foil with your finger and move it along the grid line to check for breaks.

1. 1
   Turn on the heater switch and use the voltmeter to measure the voltage of each heater line at the center point of the glass. If the voltmeter reads approximately 6 V, the rear window defogger line is considered satisfactory.

   

2. 2
   If the heater line between the center point and terminal (+) is broken, the voltmeter will read 12 V.

   

3. 3
   If the heater line between the center point and terminal (-) is broken, the voltmeter will read 0 V.

   

4. 4
   To check for open circuits, slowly move the test lead in the direction where the open circuit appears to exist. Try to find the point where the voltage becomes 0 V or changes. The point where the voltage changes is the open circuit point.

   

5. 5
   Using an ohmmeter, measure the resistance of each heater line between the terminal and the center of the grid line, and between the same terminal and the center of an adjacent heater line. The section with the broken heater line will show twice the resistance of the other sections. In the affected section, move the test lead to the position where the resistance changes sharply.

   

6. 6
   Conductive paint.
7. 7
   Paint thinner.
8. 8
   Insulating tape.
9. 9
   Silicone remover.
10. 10
    Using a fine brush: Clean the glass near the broken heater line, clean the adhesive remover with silicone, and attach masking tape as shown in the illustration. Shake the conductive paint container and apply three coats with a brush at intervals of approximately 15 minutes. Remove the tape and allow sufficient drying time before applying power. For a better finish, scrape off excess deposits with a knife after the paint has fully dried. (Allow 24 hours.)