Rear window heater

[Salwayne]

The rear window heater on my 320I does not work, when i press the button on the dash it lights up but the window does not de-mist. I was wondering if anyone has any pointers on fault finding the circuit/where the best testing/checking points are???

[Brianmoooore]

Chances are that the problem is with the rear window itself. If there's absolutely no action whatsoever from it, then check that one of the connector blocks half way up each side of the screen hasn't become detached from the glass.
You should have 12 volts between the two thick vertical strips at each side of the screen, and, on a working screen, you should be able to measure 6 volts on each element strip half way across the screen.
Any damage that is physical rather than just corrosion, can be repaired using two pack conductive paint applied to a CLEAN surface. IMHO, the single pack equivalents aren't worth bothering with.
Also bare in mind that damaged glass is usually covered by comprehensive insurance policies, without prejudicing any no claims bonus that you may have.

[Salwayne]

Thanks for the information, il check the voltages when i next get chance, is there a relay in the circuit? i also havent had chance to check the fuse which i am led to believe is fuse 8???

[Brianmoooore]

Fuse is #8, but the switch wouldn't light if it was blown. No relay.