How Do You Troubleshoot A Rear Window Defogger?
Most rear window defoggers are part of simple circuits that are easy to troubleshoot. The grid on the back window consists of a resistance wire that heats up as current flows through it, defogging or melting the ice from the glass. Although manufactures may use grid resistance variations, the circuit configuration remains pretty much straightforward. We will go trough the steps necessary to locate the circuit malfunction, from the actual grid to the fuse or circuit breaker. All you need is a very basic understanding of electricity or the desire to learn basic troubleshooting procedures. Check the defogger circuit fuse and make sure it is in good condition. If necessary, replace it. Turn the ignition switch on but do not start the engine. Turn the defogger switch on. Open the driver’s door and look at the dome light inside your car. The light should barely illuminate. If the light is not dim, go to Step 9. Inspect the defogger grid on the back of the window. Start the engine and turn on
