AirSpeed VW Community Forums

Technical => Electronics & Car Audio Forum => Topic started by: HeliMike on November 04, 2005, 03:49:54 PM

Title: Rear Defroster
Post by: HeliMike on November 04, 2005, 03:49:54 PM

*Dumb question of the day*^_^

I was just sitting here wondering why in the hell my rear defroster has NEVER worked on any aircooled VW I have ever owned? Even my untouched (before I owned it) fastback's rear defrost doesn't work but absolutely everything else does. Is there a common problem with these things or do they just suck ass and not work right from the plant?

Title: Rear Defroster
Post by: Hansk on November 04, 2005, 10:37:54 PM

Ya , it's the element in the window. Probably only good for about 20 years or so. [_[  

Title: Rear Defroster
Post by: Bruce on November 04, 2005, 11:34:05 PM

Hans is right, the traces on the window degrade to the point where they don't conduct electricity.  Replace your window with a new one and you have another 20+ years.

My theory is that the ammonia in most window cleaners is corrosive to the thin metal traces.  That's why I wash the inside of my window with only very mild soap and water.  Then I wipe it with a clean water soaked cloth to remove the soap residue.  My window has the VW logo and says \"Made in USA\", so I know it isn't an original 30 year old window.

Three years ago a friend of mine bought a new defogger window from Gildford VW for his 71.  I believe it was under $300.  It is not a bad deal since they pay for shipping to Surrey, and if it breaks on the way, you are not responsible.

Title: Rear Defroster
Post by: HeliMike on November 05, 2005, 11:31:17 AM

20years? That's it? ^_^

Thanks guys  :rockon:
 

Title: Rear Defroster
Post by: GRK on November 05, 2005, 02:47:00 PM

you could put an ohm meter on the strips and find out where the break is . there used to be a product I think Lordco sold to patch up strips works for a while might get you through the winter?

Title: Rear Defroster
Post by: Bruce on November 05, 2005, 09:48:23 PM

Quote

you could put an ohm meter on the strips and find out where the break is .

An ohm meter won't help you find the breaks.  It doesn't matter where you touch the lines with the test leads, there will be as many as 7 other paths for the cct.  

The only info an ohm meter can tell you is how many of the lines work.  Put the test leads on the 2 power terminals and measure the whole grid.  If it's completely shot you will have an open cct.  A new one will be about 4 ohms, IIRC.