Examination
Warning! To test the rear window defroster, wrap the voltmeter probe with aluminum or tin foil to prevent damage to the defroster conductive strip. To determine the break, you need to press the foil with your finger and move it along the conductive strip.
1. Start the engine and turn on the rear window defroster. Connect the negative lead of the voltmeter to «weight» car. Connect a voltmeter lead in turn to the center of each conductive strip of the rear defroster. The voltmeter should show a voltage of about 6 V.
2. If the voltmeter shows a voltage of 12 V, then the conductive strip of the heater has an open on the side between the voltmeter connection point and the side of the heater connected to «weight».
3. If the voltmeter shows a voltage below 0 V, then the heater conductive strip has an open on the side between the voltmeter connection point and the side of the heater connected to the positive battery terminal.
4. To determine the break point, move the probe along the conductive strip of the heater in the appropriate direction. The point where the voltage indicated by the voltmeter has changed abruptly is the break point.
5. Using an ohmmeter, measure the resistance of each conductive strip between the side terminal of the heater and the center of each strip. The section of the strip that has a break will have a resistance twice as high as the resistance of the rest of the heater strips.
Heater Conductive Strip Repair
1. To repair the conductive strip of the heater, prepare the following materials and tools:
- conductive mass;
- finely dispersed conductive mass;
- sticky tape;
- solvent;
- brush.
2. Wipe the area of the glass near the break in the conductive strip of the heater with solvent and stick strips of adhesive tape on both sides of the conductive strip.
3. Apply three coats of conductive compound at intervals of 15 minutes. Remove the adhesive tape and wait until the conductive mass dries. After 24 hours, use a sharp knife to remove excess conductive mass.
Warning! After restoring the conductive strip of the heater, clean the glass along the strip of the heater with a slightly moistened rag.