Open defogger filament
 

On our '86, we have an open filament within the center defogging element.

Only one filament is defective.

Any way to correct this issue without a major surgery?

Thanks in advance,

Gerry

http://forums.pelicanparts.com/uploa...1266516613.jpg

You can get a kit to fix it at about any auto parts store.

It's a conductive 'paint' that goes on over the break.

If you mask and apply carefully it's not too noticable.

You can get this at any decent Auto Parts Store. I have repaired a few defrosters, works great. One tip, ythe brush they give you sucks. Go to a place that has paint brushes for artists and get a 4/0 or 5/0 brush.

http://www.permatex.com/images/Displ...otos/15067.jpg

http://www.permatex.com/products/Automotive/specialized_maintenance_repair/auto_glass_lens_repair/Permatex_Quick_Grid_Rear_Window_Defogger_Repair_Ki t.htm

Thanks for the tip.

I did call Permatex, and was advised that the product they offer will not work on a single filament repair.

Additionally I was advised to contact a "window" specialist.

Thanks again,

Gerry

Gerry:

What!!! There seems to be a miscommunication. I have repaired several lines with this stuff.

You just find the break in the line and paint on the stuff. I am assuming you are referring to one of the lines across the width of the windshield.

how did you check the filaments?

Don't know how Gerry will find the break, but my method once you find a dead one:

1-Put the key in the run position (note engine does not need to be running);

2-Set your volt meter to a suitable range (mine is set to 0-5 or 0-25 volts dc).

3-Connect the negative lead to a ground inthe car;

4-Turn on the defogger;

5-Touch the positive lead to the suspect line. If it reads zero volts, move down the line towards the driver side until you get a reading. If it reads some amount of volts, move down the line to the passenger side until it stops reading (the reading will decrease as you get closer to the passenger side).

6-The spot where the reading stops is where the break exists.

Sometimes you can just see the break. Use the voltmeter to confirm.

That's the stuff I was talking about.

I've used it also. Worked fine.

can you just check for continuity along the line?

Carl,

Use of an ohmmeter does not work well because the individual lines are connected at both ends to a common "bus". You would be looking for a small change in resistance that you may or may not see. I find that the voltmeter method works very well.

ahhh, that kinda makes sense. I just got a multimeter and am trying to figure out how to work the dern thing. lots o' features.
thanks

Thanks,

I'll try a loop that is used for viewing slides and negatives to check for the location of the open circuit.

Perhaps I did not communicate the issue to the folks at Permatex, however I thought that I was quite specific as to the single filament open circuit.

The defective filament became quite obvious during the use of the defogger ckt
last week.

Question:

Is the filament exposed out of the glass on the inside of the window?

Thanks to all who responded to this anomoly.

Gerry

Yes, it is exposed on the inside of the glass on my car. If you run your finger over it, you will feel the roughness.

Hopefully you will find the break visually, if not a $5 Harbor Freight voltmeter will do the trick.

The defective filament was obvious during use.

I used a multimeter set on the VDC scale, connected the - to ground, and very lightly probed the defective filament from the inside on the driver's side, to the passenger side.

When I lost voltage, the open was located.

Good luck,

Gerry