Hi, I have never had auto dimming mirror on any car before.

Any advice on how to test if the auto rear view mirror is working?

Drove the car at night for the first time this week and did not think it was working. Switching it on and off did not make any difference. The green light is working ok.

Does the centre rear headrest cause a problem?

Is there anything else I need to check?

Thanks

Gerry

When you switch the mirror off it can take some time to re-act. Were you sitching it off and expecting an instant change?

When you switch the mirror off it can take some time to re-act. Were you sitching it off and expecting an instant change?

Most probably.

To test when it's dark cover the sensor on the back of your mirror (the square facing the windscreen) with your hand and shine a torch on the sensor on the front of the mirror -what triggers the operation is the difference in the amount of light hitting the back and front of the mirror. It should go green or blue progressively

The way I knew mine was working was being able to see nothing but two dimmed out balls of light behind me on a congested motorway. It was way too dark so I plugged the rear-facing sensor with a bit of blu-tac and I can see behind me in the dark on motorways now.

And before anyone says, I had any eye test last month and all is well in that department

To test when it's dark cover the sensor on the back of your mirror (the square facing the windscreen) with your hand and shine a torch on the sensor on the front of the mirror -what triggers the operation is the difference in the amount of light hitting the back and front of the mirror. It should go green or blue progressively

Thanks I shall test it out.

Yes the third head rest can be in the way depending on the angle of the mirror.

mine reacts slowly, and the difference is minimal and hardly noticeable (glad I didn't spec it as a cost-option on a new car!) The one on my wife's Mini is considerably more effective.

Edited 15 May, 201214 yr by sidewaze samm

Hi, Thanks for the advice.

I have just tested the mirror with a torch and this proved it is working ok.

I will remove the headrest to see if that makes any difference.

Gerry

With age, these mirrors seem to start to leak - the original manufacturer did fix them for a standard charge in USA market. When mine failed on my 2000MY B5 Passat, I looked out for secondhand ones, but considering the fact that mine started to leak and there was history of this, I dug deep and ordered the later version, ie the one with an ON/OFF switch and fitted it, one reason for that was that I had spec'd that option on my wife's Polo and always wished that my car had that version to cover the situation in a previous posting - ie not seeing sidelights following you in town sometimes.

A strange/stupid story, but, as my car originally had the early version with no OFF/ON switch, when my wife's Polo came near the end of its warranty period, I was going to hand it in to get the mirror sorted as it (now) did not work - wrong, one of us had switched it off - now discovering that saved a bit of embarrassment!

Edited 16 May, 201214 yr by rum4mo