Heat Wire Inspection

CAUTION: When wiping off the stain on glass with cloth, use a dry and soft cloth and move it in the direction of the heat wire extension to avoid damage to the heat wire.

Prepare the following checking items.
- Liquid crystal thermograph sheet (Approximate Size: 300 300 mm (11.8 11.8 in) and thermal temperature: 35 - 40°C (95 - 104°F))
- Aluminum foil
Turn the ignition switch to ON.
Turn the defogger switch to ON.
Push the liquid crystal thermograph sheet from the outside of the rear glass.

Fig 1: Liquid Crystal Thermograph Sheet
Courtesy of SUBARU OF AMERICA, INC.

NOTE: Use the liquid crystal thermograph sheet every range it is separated with the separate line.
Determine the faulty heat wire by checking the color of the liquid crystal thermograph sheet.
NOTE:
- Check from the inside of the glass if the liquid crystal thermograph sheet does not change.
- The time for the color change may differ depends on the surface temperature of the glass.
Wrap a piece of aluminum foil around the tip of tester probe and press it against the heat wire with your finger.

Fig 2: Applying Conductive Silver Composition To Broken Portion
Courtesy of SUBARU OF AMERICA, INC.
Fasten the tester probe on the positive (+) side and negative (-) side to end of positive side of open harness of step 5.
Move the tester probe on the negative (-) side slowly along the heat wire. If voltage changes from zero to several volts during movement of tester probe, heat wire is open at the voltage change point.

Fig 3: Checking Heat Wire Voltage Change
Courtesy of SUBARU OF AMERICA, INC.
Repair the heat wire that determines the place of the open circuit. Refer to GW-29, REPAIR , Rear Window Defogger System.