Printed Rear Window Defogger

Repair Procedures

Inspection

1. 1
   Turn on the heater switch and measure the voltage of each heater line at the center of the glass with a voltmeter. If the voltmeter reads 6 V at a conductive line, the rear window line is considered in good condition.

   

2. 2
   If the conductive line is broken in the area between the center and the (+) terminal, the voltmeter will show 12V.

   

3. 3
   If the conductive line is broken in the area between the center and the (-) terminal, the voltmeter will show 0V.

   

4. 4
   Check for open circuits. Slowly move the test lead along the section where an open circuit is suspected. Try to find the point where the voltage changes to 0 V. The point where the voltage changed is the open circuit point.

   

5. 5
   Use an ohmmeter to 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 a broken heater line will have twice the resistance of 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: Wipe the glass adjacent to the broken heater line, clean it with silicone remover, and attach adhesive tape as shown in the illustration. Shake the conductive paint container and apply three coats with a brush at approximately 15-minute intervals. Remove the tape and allow sufficient drying time before applying power. For a better finish, scrape off excess paint with a knife after the paint has fully dried. (Allow 24 hours.)