Hi all,
So like many folks I'm suffering a non-operational rear demister on my '07 Outback wagon, but the symptoms don't fit all the threads I've read on the subject (here and elsewhere).
The basics; the dash switch is functional, the light comes on when the button's pressed and goes out after the timer period, the relay clicks, both fuses are sound.
Originally I was indeed affected by broken wires in the tailgate boots; replaced sections on the broken three wires (including the hot wire to the demister) and all was well - for a few days!
The situation now is that I get 0V measured at the +12 side of the grid, however if I unplug the grid at both sides and measure at the plug I've taken off the hot side, I get 13.5V! Plug it in and it sucks down to 0V again.
Now I can't see how the grid could possibly be a dead short, as it were - yes there's an electrical path across it but the whole point is that it's somewhat resistant else it wouldn't heat up right? I mean many folks talk about having broken lines across the glass but no-one talks about having ultra-conductive lines right?!
I also noted that (with the engine not running) I seemed to measure 10.5V before the weird condensor unit that's attached inside the tailgate, but 13V or so after it (voodoo, like I say). Can it be that some part of the signal path is adequate to pass a bell-test or measure a good voltage but when it's expected to pass a serious current (to operate the grid on the glass) it 'fades' and can't pass enough current?
So any suggestions folks? I'll admit to finding electrics to be voodoo - I'm much happier with digital systems where things are just on or off
Thanks,
Ian