Heated Rear Window Problems

[white90]

The following supplied by ADS, Thanks

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The usual problem s that the voltage sensing relay has gone faulty and yes you can do without it.

The feed from the switch just operates the coil of the relay in series with the volatge sensitive switch (hope I am not losing you here !). The voltage sensing relay was put there to ensure that the heated rear window element could only be operated if there was an output from the alternator. As the control relay is initially fed from the ignition side of the switch it would only work if the ignition is on - so why worry about this VSR ? It is a costly item to replace and something you can do without.

First check the switch has a feed to at least one side of the switch then measure/check the voltage from the other side of the switch down to earth to determine whether the feed goes through the switch. Check the switch in fact operates - they are a cheap and nasty switch that do fall apart. I would then undo about 4 screws to release the instrument panel - try to ease it forwards as much as you can so that you can shine a torch down behind to the bottom right to see if you can locate the yellow plastic relay and the black one (they are both about 1 inch square). These are tucked a fair way down and are a push fit onto a metal 'tongue' that is fixed to the rear of the bulkhead. ease both relays off their fixing so that you can get to the wiring on the bottom of them. The length of the wiring to these are not over generous and you might struggle a bit with this.

What you need to do now is to remove the black/pink cable from the coil connection of the black relay and put some insulating tape on the bare end/spade terminal as this goes off to feed the voltage sensing relay in series with it (you won't need this relay again and if you tape it up it will make it safe - you can then put the yellow relay back). Now make up a length of black cable and put a spade connector on one end and connect this back onto the same relay terminal that you removed the black/pink cable from. The other end of this cable should be put down to a convenient earth point on the metal bulkhead (use a circular terminal, shell washers anything that a bolt or self tapping screw will hold firm). If you now operate the heated rear window switch you should hear the black control relay click and if the lamp is in order you should illuminate the symbol on the dash.

The next bit is to put the black relay back on it's tongue/post - easier said than done as it is a bit fiddly and hey presto the job is done bar putting the instrument panel back remember to changee any of the 'knackered' panel lamps at the same time, they are very easy to do - just a 90 degree twist.

Well it sounds easy doesn't it - it is but just fiddly. I did mine in the dark as I could see what I was doing better behind the instrument panel from torch light.

Regards

ADS