Attention! See the warnings at the beginning of the Section Check of serviceability of functioning and replacement of the breaker of indexes of turns / alarm system and the switch of the last.
1. The working element of the rear window heater is a horizontal grid of conductive threads glued to the inner surface of the glass. The heater is activated using a switch located on the dashboard of the car. Check the function of the switch (see Section Check of serviceability of functioning and replacement of the switch of heating of back glass).
2. Small breaks in the conductive threads of the grille of the working element of the heater can be eliminated without dismantling the rear window.
Examination
1. Turn on the ignition and rear window defroster. Press the positive probe of the voltmeter to the positive terminal of the heating element grid, press the negative probe to the ground terminal. The device should register battery voltage, otherwise check the condition of the fuse, switch and connecting wiring. If the voltage is OK, however, part of the heater is not working. Proceed to the next step of verification.
2. In order to measure voltage during the tests described below, wrap the positive probe of the voltmeter with metal foil, which can be easily pressed with a finger directly to the conductive thread of the heating element grid (refer to accompanying illustration). Connect the negative probe of the meter to the grid ground terminal.
3. Measure the voltage in the central part of each of the lattice threads. A reading of 5 - 6 V indicates that the thread is in good condition. A zero reading indicates a break between the center of the thread and the positive side of the element. Double reading (10 - 12 V) occurs when there is a break between the center of the thread and the negative side of the element. Check each of the lattice threads one by one.
4. If there are no breaks, connect the negative probe to the chassis ground and repeat the test, the readings should not change, otherwise there is a violation of the grid grounding quality.
5. To localize the break, press the negative probe of the voltmeter to the negative terminal of the heating element grid. With a positive probe wrapped in foil, begin to probe the conductive threads of the grid, moving from the side of the power supply to the ground. At the break point, the instrument reading should drop from a few volts to zero.
Refurbishment
1. The integrity of the conductive threads is restored using a special two-component electrically conductive paste of the Dupont type No. 4817.
2. Turn off the heater and allow the element to cool for a few minutes before refurbishing the work element grille.
3. Lightly clean the damaged area of the thread with felt, then wipe it thoroughly with alcohol.
4. Apply two strips of tape along the thread to be repaired.
5. Thoroughly mix the epoxy paste with the hardener (follow the instructions included in the kit).
6. Apply the resulting composition to the damaged area (with an overlap of about 20 mm on the edges of the intact thread) (refer to accompanying illustration).
7. The final polymerization of the compound occurs after 24 hours, after which the protective tape strips can be removed from the glass.