306 estate rear demister

[cully]

First off heres the electrical drawing
this should help when fault finding

first off you need to check the fuse's all 6 of them!
if the fuse's are ok, is the relay clicking when you push the switch? try replacing the relay first
check Voltage at pin 1 and to ground on the rear heater?
check same pin1 via different ground on the car body not the tailgate?

if you have no voltage you probably have a broken wire!

to check said wire's
set meter to continuity (ohms) touch meter leads together should read very low
turn ign off,
to check the ground wire.
touch one meter lead to the ground side of the rear screen and the other to the car body,
this will check the earth from the hatch, to the car for a break should read very low

to check the switch + wire
unplug the + wire at the rear screen/ unplug the relay
touch one meter lead to the + wire at the screen and touch the other wire to pin5 at the relay base (double check you get the right on) reading should be very low

if it is high you have a break which will probably be at moving points in the loom