SC Defogger

Does anyone know the exact workings of the '82 or similar defogger/defroster system?

The manual talks about a setting which also defogs the windshield. Is this tied into the front defroster (blower) or is it an electrical defogger?

Also, when I pull the defog/defrost switch, only about four lines of the heating element energize. They are centrally located in the rear glass, but not right next to each other. Is this a rapid defrost feature, or do I have some continuity problems in the element? I'd like to test the continuity of each line of the element, since there are some dark spots on some of the lines, but I'm not sure if the lines are embedded in the glass or covered by some sort of coating.

Any information, advice, or experiences would be appreciated.

Thanks,

Olivier
'82 SC

I've got similar problems with my rear defrost as yours. Some of the lines are broken, but there is not much that you can do about it other than replace the rear glass. Maybe there is a way to fix a broken line.

I don't know if electrical defrost was available on an 82 SC. My 79 SC doesn't have it. The defrost controls on the dash allow you to select either hot air from the rear heater blower, or fresh cool air from the fresh air blower, or a mixture of either. The owners manual does a good job of describing how it all works. It's not very intuitive.

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Bill Krause
'79 911SC Euro

I've seen repair kits to repair the lines on defrosters, so some systems must have the line accessible (besides the cheap, taped-on systems).

The kit was at a local parts store, and consisted of a small template to prevent overrun and a small bottle of liquid conductive material.

Maybe I'll buy it and see if the instructions mention how to determine if the lines are accessible. From looking at my lines, I may need a gallon of the stuff!

Olivier

I have a '84 Carrera. My rear defogger is a two stage arrangement. When you pull the defogger knob out, that is stage one. You then twist the defogger knob (it clicks after about 1/4 turn), and you are in stage two. Stage two puts the highest wattage to the defogger and energizes all the thin wires on the rear glass.

I do not have any electrical heating element on my windshield (only OEM heat and a rag), so I can't help you much on that topic.

Regards, Bruce

My switch works the same way. I can also turn the knob clockwise without pulling it. Is that a different setting. The owner's manual says that pulling provides a steady heat and turning provides maximum defogging. I can't remember which one mentions involving the "windshield"

Olivier