Unexpected Reanimation ? ? ?

[ARCHINSTL]

Goldie's hatch window defroster has never worked since I got her in 2005.
I've tried the various testing procedures, but due to my ineptness, was never able to isolate the problems; granted, several lines were obviously broken, but since the "main lines" on the sides were intact, I figgered at least some of the horizontal lines would work.
They never did - oh, well.
I also checked all of the connections and relay, fuses, etc., and all were OK.
My last attempt was in 2013: viewtopic.php?f=4&t=9569&hilit=grid
Based on my clumsiness with attempting to repair lines on another vehicle decades ago (with steadier hands!) with the Permatex kit, I did not go that route, but just put up with it.

Flash forward to last night. It was exceptionally humid, with monsoons continuing well into the night.
All windows were well-fogged when I left a HS bball game. I thought, "Oh well, let's turn on the defrost switch and see if anything happens."
Mind, this is the first time that switch has been touched in literally years.
All, save two, of the grid wires worked!
- - -
Ideas?

And anyone use this product? https://www.frostfighter.com/doctor-defroster-video.htm
With shipping, it is almost double the Permatex kit's price at various supply stores.
Extremely interesting site, with lots of info! Many different products, all for various defrosting probs!
Tom M.

[Petros]

you have one of those fabled self repairing cars, ignore the problem long enough and it goes away.

you may have over time, doing other maintenance or service, bumped or unplugged/plugged in a critical connector that had corrosion in it and fixed the problem. Or possible the wire bundle is worn through and grounding, and it got moved or repositioned to not be grounded any longer. without chasing the wire from switch to heating element, and inspecting its condition, you may never know the cause.

I have seen similar defroster repair products before, seen car dealers use them. but I have no experiance with it, and I need to give it a try, about half of mine are out.

[LowBuckCanuck]

The e-brake light has been on the entire winter in Lenny. A week ago, I put the handbrake on, then off, and it went out. It works perfectly now.

One of Lenny's marker lights didn't work. I hit it once with my fist, and now it works.

I am now a firm believer in "unexpected reanimation" as you call it.

[ARCHINSTL]

@ LowBuckCanuck - now there might be a clue!
I don't think I've slipped it into the 4WD mode in couple of years - I use the p'up on the few "snow days" we've had here.
However, Tuesday night I used it for a couple of hundred feet while starting on a steep, very wet, and worn-smooth pavement hill.
I had no need of 4WD the rest of the night.
I did not try the defroster until a few hours later.
I wonder ...
Tom M.

[splatterdog]

There's a chance there's a broken wire where the harness comes out of the car. Sometimes the ends touch, sometimes not kid of deal. But that's if there's no voltage at the grid terminals when it's not working. Hook up a volt meter at window, turn defrost on, open/close hatch and wiggle test exposed harness.

[ARCHINSTL]

Will do - thanks!
Tom