Heated mirrors going on and off randomly

[ruaricoles]

Hello peeps,

The heated mirrors (or rather mirror, as the passenger side one has never worked) have started turning themselves off and on randomly. If they're off, you can always turn them on by pressing the fan switch as you would expect, but they don't always go off after the preset time and sometimes come on all of their own accord.

Does anyone know where the timer unit for them is, or where the most likely dodgy connection is?

Ta

Ruari

[roy e6]

Just looked at you profile. Automotive Engineer. And your asking us?

[The AJP Griff]

ruaricoles said:

Hello peeps,

The heated mirrors (or rather mirror, as the passenger side one has never worked) have started turning themselves off and on randomly. If they're off, you can always turn them on by pressing the fan switch as you would expect, but they don't always go off after the preset time and sometimes come on all of their own accord.

Does anyone know where the timer unit for them is, or where the most likely dodgy connection is?

Ta

Ruari

Hi Ruari,i think the heated mirror control comes from the heater ecu behind the dash(blue/orange wire out i think).If you dont find a relay at fault,then it will probably either be this 'ecu' or the control knob(blower)going faulty probbly.

[dnb]

It is indeed the blue/orange wire from the heater ECU.

There's no relay I can see. (The mirror heaters are 18 ohms, so each consumes less than an amp, so no real need)

[Uncle Fester]

The printed circuit board behind the dash is known for suffering damaged tracks.
Check it thoroughly as this is hard to spot.
Fester

[Argent]

I had a problem with this ecu once which was cured by cleaning off corrosion bridging the tracks on the back with some pcb cleaner I got from from Maplins.

A.