GM Celebrity/Century/Ciera/6000 1982-1996 Repair Guide

Rear Defogger System

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All systems operate on 12 volts. An instrument panel mounted switch with an integral indicator lamp is used to turn the system on.

Certain conditions such as outside temperature, vehicle speed, atmospheric pressure and even the number of passengers inside the vehicle affects the length of time required to remove fog from the glass.

The defogger is designed to turn off after approximately 10 minutes of operation. If the defogger is turn on again, it will only operate for approximately 5 minutes. You can however, turn the system off before the time is up by turning the defogger switch or ignition switch OFF .

REMOVAL & INSTALLATION



  1. Disconnect the negative battery cable.
  2.  
  3. Remove the left side instrument panel or accessory trim plate, as required.
  4.  
  5. On some vehicles, it may be necessary to remove the steering column collar, steering column opening filler and cluster trim plate.
  6.  
  7. Remove the ash tray and sound insulator, as required.
  8.  
  9. On some vehicles, it may be necessary to remove the radio control knobs, air conditioning/heater control and/or cables.
  10.  
  11. Remove the rear defogger control retaining screws or clip and remove the switch.
  12.  
  13. Unplug the switch electrical connector.
  14.  

To install:
  1. Engage the electrical connector to the switch.
  2.  
  3. Fit the switch to the instrument panel and install the retaining screws.
  4.  
  5. Install the instrument panel or trim plate.
  6.  
  7. Reconnect the negative battery cable.
  8.  
  9. Reset the radio, clock and any other applicable accessories.
  10.  

TESTING



See Figure 1

  1. Start the engine and pull out the defogger switch knob.
  2.  
  3. Using a test light, ground the end and touch the probe to each grid line. The test light should operate as indicated in the illustration.
  4.  



Click image to see an enlarged view

Fig. Fig. 1: Check the grid lines with a test light

  1. If the test light remains bright at both ends of the grid lines, check for a loose ground.
  2.  

The range zones may vary slightly from 1 glass to another. But, the test light brilliance will decrease proportionately as it is moved from left to right on the grid line.

  1. If an abnormal reading is observed by the test light on any grid line, place the test light probe on the left of that bus bar and move the probe toward the right until the test lamp goes out. This will indicate a break in the continuity on that grid line.
  2.  

REPAIR



See Figures 2 and 3

  1. Locate the break(s) on the grid line(s) and mark the outside of the glass, using a grease pencil.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Clean the area to be repaired. Buff with fine steel wool and wipe clean with a damped cloth with alcohol.
  6.  
  7. Position a strip of tape above and below the grid line area to be repair.
  8.  
  9. Repair the grid line break using a defogger repair kit (GM part 1052858 or equivalent) and follow the manufacturer's instructions.
  10.  



Click image to see an enlarged view

Fig. Fig. 2: The grid lines can be repaired using a defogger repair kit (GM part 1052858 or equivalent)

  1. After the grid line has been repaired, carefully remove the strips of tape.
  2.  
  3. Apply heat, (using a heat gun or blow dryer) to the repaired area for approximately 1-2 minutes. A minimum temperature of 300°F (149°C) is required.
  4.  



Click image to see an enlarged view

Fig. Fig. 3: Apply heat to the area with a blow dryer or heat gun

To avoid damage to the interior trim, protect the trim near the area to be repair. Allow the repair materials to cure for at least 24 hours. Do not operate the unit until such time has passed.

  1. Test the rear defogger operation to verify proper operation.
  2.  

 
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