Rear defroster

[kyngfish]

Rear defroster only seems to work at the top lines. The top 6 inches of the glass defrost, they rest stay frosted.

Any tips for troubleshooting?

[cpa]

Kyngfish, after you pull the switch out turn it to the right. One o'clock, there is a low and high setting.

[HarryD]

What year is your 911? On my 1973 it has two stops when you pull it out.

To check your wires, you can use a voltmeter.

For a working wire you will have 12 volts at one end and 0 at the other if the wire is working. If it is not the voltage will suddenly drop off at the break.

[DRACO A5OG]

^^^ +1

[gptom]

With a voltmeter, you will have 0 VDC on one side & 12VDC on ALL lines on the other side. Check the approximate middle & ground. Good line = 6 VDC & Bad line will be either 12 VDC or 0 VDC

[HarryD]

You can check individual lines by connecting one side of the Voltmeter to ground and run the other probe along a line.

[tcar]

If you look closely, you will probably see that some of the lines are not continuous... they are broken. Something rubbed on the inside and damaged them.
That's what causes that.

It is possible to repair them, but not easy.

[HarryD]

I sometimes have trouble seeing the lines which it why I use my voltmeter.

Permatex makes a kit to repair the lines. You can get it at most auto parts stores. As tcar notes, it is awkward to repair the lines on the glass.

Professional Repair Systems : Permatex® Complete Rear Window Defogger Repair Kit

[James Brown]

i got a little bottle of copper particles suspended in clear paint, like fingernail polish, paint it on both sides of the brake. i fixed several opens in the wire loop. at your local FLAPS

[HarryD]

Hi Jim:

The copper paint is what is in the Permatex kit. I have used it for a few cars.

[James Brown]

^^^^^^^thats the stuff^^^^^^