Hot Door Mirrors in VW Beetle

[Sylvie]

On a short drive three days ago, the passenger side door mirror became loose and shook.

I pulled into a lay by. I found that the mirror and the supporting surface beneath it was rather hot. Checking the driver side mirror, that too was hot.

Given the fact that the button for the heated rear window was not switched on ( I assume that the HRW Switch operates the heated door mirrors as well as the rear window) I checked the fuse box and found the one operating for the HRW had not blown.

Can anyone suggest what the problem might be?

Thanks in anticipation of a response?

[tonyav]

Sounds as though there is a short in there Sylvie, strange that it didn't blow a fuse though.

[Sylvie]

Thanks Tony.

What's the fix? Is it a relay that isn't switching off?

[douglas9401]

Does it happen when the car's not in direct sunshine? The heating element for a mirror isn't that big and it's doubtfull that it could radiate enough energy to heat up anything not in direct contact with it especially given the cooling effect of airflow over the vehicle.
It says two unrelated things to me.

[Sylvie]

Dougie,

Yes, it happens when the car is not in direct sunshine.

Yesterday, I drove the car from cold (including cold mirrors) in relatively cool, cloudy conditions. Within a couple of minutes - say 1 mile - the mirrors we very warm.

QUESTION.

Are these things controlled by relays that are capable of malfunctioning?

[TWR]

My own German car stops on Sylvie, it there was a fault the fues would blow, the heat element is the same size as the mirror itself. I sure if it was HOT as you say you would have trouble holding it, do you mean warm? there is obviously a difference, ( I'm not testing your intelligence Sylvie)

[Sylvie]

Hi TWR,

An AA officer had a look at it 2 hrs ago. he ran the engine for 4 minutes and found the 2 door mirrors recording temperatures at 48c. Somewhere between warm and hot. hot enough presumably to melt the solvent on the inside of the mirror.

The AA patrolman spent 45 minutes and was unable to identify the problem.

As a result, the car will be booked in to the local VW dealership.

NB. The AA guy said that smart cars have had some problems with Overheating door mirrors on Smart cars resulting in fires and the melting of the surrounding plastic mountings and bodywork.

[TWR]

As said Sylvie, It may be a faulty relay, some are on a timed switch.

[tonyav]

TWR, would the heated rear window be on the same relay ?

[TWR]

I would think not Tony, as you will know they are timed.

[tonyav]

So are heated rear windows, probably need to look at a schematic to know for sure though I think ?.

[TWR]

I gather the Heated mirror switch has to be left in the Left / right side & NOT IN THE MIDDLE, by leaving the button in the middle it keeps the heater engaged, thus overheating.

[tonyav]

Yep, didn't think of that TWR.

[TWR]

If you are Looking in Sylvie, check this out.

[Sylvie]

Thanks TWR,

Will check this out.

S