Rear Defogger Not working

[mbc]

So we have an Octavia Estate from 2001, 1.6 AVU engine and the rear defogger is not working. It does not have Climatronic. We bought it 2 years ago, it never worked, but now I'm set on fixing it. Can you please tell if I should hear a relay noise when I press the defogger button? There is no sound of any relay, but I know that some cars don't have a relay for this. If it has a relay, it would be useful to know where is it located and which one is it.

 

Thanks!

 

PS: Have not figured out how to add this car to the list yet.

[KenONeill]

@mbc - It's a purely electrical thing yes. I've never heard a relay, so would start by checking the fuse, and then continuity checking the wiring (particularly if the rear number plate lights and/or wiper also don't work).

[mrgf]

Not got an Octy but have a close look at the wiring going into the hatch to ensure they are solid and not fractured. Also, do the same where the terminals connect to the actual heating elements. Do a circuit test to see if its live. There sometimes becomes issues with the actual element strips, too, which can break and you can quite easily purchase a kind of liquid metal kit from auto shops to "Paint" where any break may be.

 

This is just general info and not specific to any brand.model.

[mbc]

Thank you,

 

Everything else works on the hatch - number plate lights work, wiper works so everything is good except the defogger.

 

I wil check the fuse and maybe start taking plastics off to have access to the circuitry.

[Devil69]

Hello, mbc,

 

It might also be the broken connectors on the rear glass. Have them checked with a multimeter.

I hope this helps.

 

Regards,

Dragoș

Edited 9 January, 2019 by Devil69

[Liger1956]

As mrgf said my money is on the heater wire being broken in the umbilical between the body and the hatch. The rear screen heater wire is normally the thickest of those wires and is, in my experience, the first to break. You will need to pull the rubber umbilical off the body and the hatch to be able to move it both ways to inspect for any signs of breakage. The conductors may be broken but the insulation may still be intact so you may have to look closely.

[mbc]

I checked the fuse, the fuse is ok. It will probably check the wires on Saturday so I have enough time to do that during daytime.