[ant76p]

Hi Guys,
Could anyone shed some light on a issue i have with a rear window demister not working.
The switch is fine , the mirror heaters work fine ( fuse and relay is OK)
but no live getting to the connections on the rear window.
I'm asking before i get down and dirty by stripping all the wiring back all the way through the car to find the break.
  have looked through the forum history but to no avail.
my car is a
07 1.6crdi i30 hatch.
I will be very grateful for any help.
Ant

[Asterix]

Are you sure it's same fuse for mirrors as the rear window..? On my 2008 there's a 10 A for mirrors and a 15 A for "deicer" Don't know if deicer is rear window heating.

Don't know if Hyundai suffer from this, but my experience from VW is that the cables break in the rubber grommet from the cabin to the tailgate.

[sundiz]

So you don't get any voltages to the terminals of the rear window? And if the switch and fuse are ok, it seems the issue is in the cable between the swirch and rear window. I would try to find the broken cable domewhere near the rear door. I would guess the cable near the rear door hinge is stressed most.

Some old Saabs had lots of issues with the rear window heating. In those the actual resistor network was usually broken. Those were fixed with conductive glue/paint. That would be easy to check. Just measure the resistance of the resoistor line with multimeter.

[The Gonz]

'stripping all your wiring' sounds pretty drastic. When tracking down such a break, apply the half split rule, by starting with and end-to-end continuity check (which you have done), then find a convenient point in between (such as wherever the wiring is easily exposed without tearing the car apart) and check continuity again back to each end point. Whichever side reveals the break, keep 'half splitting' at convenient points until you are down to a single length of cable, connector, fuse, whatever.

Works for computers, TVs, cars, aircraft, even ships!

[ant76p]

well im going to try and trace it today. i will ad a update as soon as i find someting.