Wing mirror heat element code/error

[TeddyRuxpin]

Hi there - I have an error with my wing mirror - I notice that it doesn't defrost too.

Pics of the error attached. The code reads "The output for the mirror heater has a malfunction. There is a short circuit to positive or an open circuit".

I've tried changing the two connecting wires around but it makes no difference.

Do you think the error will be with the glass (i.e. heating element in the glass and therefore fixed by replacing the glass), or something else?

How's best to diagnose?

It's not a huge deal, but might be a bit annoying as winter approaches.

Thanks!

 

[Ted]

Put a test light on the two wires, switch on (might come on with the heated rear window)and see if it illuminates.
If it doesn’t, try the same on the other mirror to check the test method is correct.

 

[Supernoodle]

I'd go straight in and check the resistance of the mirror heater element with a multimeter.
Should measure in the ohm range. Both of mine failed open circuit, so easy to test.