This afternoon I went to load some boxes in the back of my Defender and happen to notice a few sticky brown spots on my tailgate. I cleaned it up thinking it could've been coffee residue from when I had several boxes of coffee in the back, but then I saw parts of the rear defrost wires were blotched and rusted. I now think that maybe these brown spots were dried up rusty water drops from when I have had the tailgate open in the rain in addition to the other water spots that show up on the Lunar colored-plastic. I have attached some pictures below. Has anyone else noticed this before?

 

I had that happen to me in a different car and I ended up replacing the rear glass. If your Defender is still under warranty, LR should replace it. Water should not cause these lines to rust out.

 

How is that possible as the heat wires are imbedded in the glass

 

They are printed on the glass

 

Yeah, the wires are exposed on the backside of the glass. The front heated windshield has wires imbedded in the glass.

 

I think it's normal. Common thing on cars for these wires to turn green, brown, rust, etc.

Wires are copper. (I think? Or a copper alloy). Which oxidizes and discolors with environmental exposure. And contact with cleaning chemicals (ammonia in bad window cleaner for example).

Rear defroster elements here are adhered to the inside surface of the glass, they are not inside or embedded inside the glass (as with the windshield heating elements on a Defender, for example).

Do those lines still work on the rear defroster? If so, not an issue functionally.

I have definitely wiped rear defroster lines on an older car before with a white paper towel and noticed a bit of discoloration wiping off on my rag from the same thing.

Also my hounds definitely jump on the rear window and scratch those elements, and I can see little lines that are corroded where their claws have "struck".

 

That's good to know, thanks! I never noticed rear defrost wires rusting in any of my other cars, but I guess there's no need to worry unless it decides to stop working.

 

As long as there are no breaks in those lines, your defrost function will continue to work. Once there is a break, the defrost will quit working.