Rear Defogger Working (but not really)

Ladies/Gents,

With the cold weather coming, I thought it would be a good idea to get that rear defogger working on my 72 SB. After a quick search of this group, I was able to determine that all is in working order. The switch is good, the fuse is fine, the relay seems to work just fine and the little green light in the speedo lights up like it should.

Per Speedy's suggestion, I checked to make sure I am getting juice across the grid. 13V across the element in the back window. So it seems like everything is in working order.

However, the defogger is useless. I know it is working because there is no condensation on the grid when it is on. But the rest of the window is still fogged up. Almost seems like it isn't strong enough to clear the rear window. After 20 minutes, it cleared only 1 mm to each side of the grid. I still can't see out the rear window.

Any suggestions?

Thanks for always being there, Juan

Reply to
Juan
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Clean connections.... most likely a bad ground.

Reply to
Eduardo K.

Thanks Eduardo,

I will do that tonight and let you know how I make out. Question: Can the grid be cleaned to make it more conductive. Mine seems tarnished but unbroken. It looks like the grid can be polished up but I do not want to start messing with it for fear of splicing it.

Based on everything that I have been reading, I should be thankful that it even works at all.

Juan

Reply to
Juan

Directly on top of the glass there is a layer that is dark brownish red that, for want of a better term, I'll call a primer. It is non-conductive and is quite durable. After all these years, that's the only thing that most people have left.

On top of the "primer" there is the resistive coating which is the actual heater element. That material is metallic and silver colored. Unfortunately it corrodes, so in the climates where it would be useful, it is almost always corroded away.

If you try to clean it off, it is most likely that you will remove much of the remaining metal layer, and this will probably destroy the heater element. From the outside of the car it will still look the same because the primer will remain, but the active part of the heater element is quite fragile and easily damaged, even by careful cleaning.

Yes, very lucky. Very few of these still work.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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Reply to
Jim Adney

There's no source for new windows with the elements intact or for kits to install such elements onto bare glass? Hmmm. I don't think mine has ever really worked but I hardly ever need it here in DFW.

Reply to
Michael Cecil

I bought a kit from JC Whitney a few years ago. Had plastic tape over metal strips and some more metal strips down the side.

When I plugged it in, only two of the strips worked (I'm sure I wasn't careful enough) - but that's enough that I can see out the window after a couple of minutes. Even when it's frosted.

I haven't seen the kit >

Reply to
Earl Brown

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Reply to
Joey Tribiani

I checked with VW about 20 years ago to see if I could get a replacement squareback heated rear window. There was exactly ONE in the US (somewhere in Texas) and they would be glad to sell it to me for $400 (1985 dollars!) I passed. Beetle rear windows might actually be available sitll, but I wouldn't expect them to be cheap.

You can probably buy repair kits at your local FLAPS. It's just a conductive paint that you use to bridge across places where the original stuff is gone. I've always wondered how hard it would be to do a really careful maksing job and re-do a whole window. I've never been quite motivated enough to try it.

In Dallas, I don't think I'd even give it a moment's thought.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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Reply to
Jim Adney

Yikes. I bought my bug in 1983 for only $900.

Exactly. I was just curious like the OP. I think mine works but it's still disconnected since I redid the window rubber (that rear window is a pain to do yourself) a few months ago.

Reply to
Michael Cecil

Over this side of the pond, you can ( got one) a brand new square window with real elements for £100.

james

Reply to
Juper Wort

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