Heated mirrors question

Rainy morning, driving through 3km long tunnel, both side mirrors foggy, I said 'what a hell, I'm pushing the button' - and they both cleared up in 4 seconds :)

I have no idea what brought the left one back to life, the last time I checked was when I replaced the whole mirror interior and cables with those from chb's mirror and it didn't want to work.

Check the mirror again an hour ago, it heats up fast and as good as the right one!

Thank you, chb :)
 
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6stings said:
Amd it's not heating again!? Mistery!
Click to expand...

Could it be the wiring connections being disturbed when you open and close the door?
So, sometimes there is a good contact and other times not? It seems to be the only variables.

Steve B
 
Hmmm, strange! One of my mirrors is doing the same and Matt's A2 also has a similar problem.

Would like to get to the bottom of this problem...
 
I've finally fixed this. :cool:

The heated mirrors are fed through the window control module. I can't remember exactly from when I did the rear electric windows what two of the feed wires to the door are, but I'm pretty certain that the heated mirrors are switched on or off via CAN commands sent to the door modules. As such, power wires for the heated mirrors do not pass through the door into the car; they connect to the door module.

Regarding how I fixed it, well ultimately, it's to do with the connection between the mirror terminals and the terminals on the wires in the mirror housing. After disassembling the door card and relevant connector, I could measure the resistance through the wires to the mirror and through the mirror glass itself. At first, there was infinite resistance measured, then after some fiddling with the mirror connections, the resistance dropped to an acceptable value of 8.8 Ohms. This highlighted the fact that the mirror connection was at fault. After some more light cleaning with contact cleaner, then a more aggressive treatment with vinegar and finally tightening the grip of the terminals on the wires end with long nosed pliers, I had a secure and electrically sound connection. Now, all is well and both mirrors work. :)

My advice to anyone facing similar difficulties would be to submerge the connectors at the mirror side in a mild acid like vinegar or maybe even coke and then tighten the grip of the terminals using pliers to achieve a better fit onto the mirror terminals. Hopefully this will fix your problem, like it has with mine. :p

For future reference, my genuine Audi heated mirrors have a resistance of 8.8 Ohms at the mirror terminals.

Matt.
 
Hi Matt,

Thanks for confirming that.

The wiring connectors on the mirror glass were the only variable left.

These get disturbed every time you open and close the door or hit a speed bump.

A word of caution to anyone buying the cheaper heated mirror glass from eBay, the connectors on the ones I tried were the wrong size and it was almost impossible to get a decent connection without crushing the end connectors to make them grip.

Thanks again Matt

Steve B
 
My mirror is working again... So looks like it is the wire connectors in the mirror housing not clamping on the glass terminals properly.

I will give them another clean and clamp them with some long nose pliers.
 
What a great thread.
Not that it bothers me hugely I just like things to work as advertised; so, my pax (LH) mirror neither heats nor moves. Drivers side works as advertised. On a scan I get front pax door won't desafe although the door locks and unlocks on the remote and shows open on the DIS.
Are the two symptoms connected.
 
simufly said:
What a great thread.
Not that it bothers me hugely I just like things to work as advertised; so, my pax (LH) mirror neither heats nor moves. Drivers side works as advertised. On a scan I get front pax door won't desafe although the door locks and unlocks on the remote and shows open on the DIS.
Are the two symptoms connected.
Click to expand...

It is very likely.

The first check is a free one, that is to remove the door card and check all connections (especially those from the door to the body).

Failing that get a VCDS check to see if there are any codes but I suspect a connection problem.

Steve B
 
wilco184 said:
After some more light cleaning with contact cleaner, then a more aggressive treatment with vinegar and finally tightening the grip of the terminals on the wires end with long nosed pliers, I had a secure and electrically sound connection. Now, all is well and both mirrors work. :)

My advice to anyone facing similar difficulties would be to submerge the connectors at the mirror side in a mild acid like vinegar or maybe even coke and then tighten the grip of the terminals using pliers to achieve a better fit onto the mirror terminals. Hopefully this will fix your problem, like it has with mine. :p

For future reference, my genuine Audi heated mirrors have a resistance of 8.8 Ohms at the mirror terminals.

Matt.
Click to expand...

Make sure that you wash off ALL the acid afterwards, otherwise it will be a short-term fix!

RAB
 
6stings said:
I couldn't find mirrors on VCDS.
Click to expand...
Sorry about that I missed the fact that you have scanned the car with VCDS anyway.

You won't find mirrors on VCDS but you will find error codes for the door issues (as you have done) and that may indicate a connection problem.

Steve B
 
Last edited:
This may not be relevant to the OP but for anyone else with heated mirror problems, I'm sure someone once said on this forum that the mirror heating only came on when the temperature fell below a certain level. Is that true or not?

Found it: http://www.a2oc.net/forum/showthread.php?8492-Heated-mirrors&p=64904#post64904
They will kick in at 5 celcius, but they also work at any temperature via the heated rear window switch [Spike]
Click to expand...

http://www.a2oc.net/forum/showthread.php?8492-Heated-mirrors&p=64923#post64923
Its therefore reasonable to assume cars with the winter pack have an additional temperature controlled circuit for the washer jets and mirrors which can be overridden by the rear screen switch [Spike]
Click to expand...
 
Birchall said:
Sorry about that I missed the fact that you have scanned the car with VCDS anyway.

You won't find mirrors on VCDS but you will find error codes for the door issues (as you have done) and that may indicate a connection problem.

Steve B
Click to expand...

I know what you mean, Steve, only the dead mirror heating seams not to affect the door card at all.

A few scans I did this summer warned about the rear left door unable to unlock, or something, without any locking/unlocking problem really.
Nothing about front doors.
 
Alan_uk said:
This may not be relevant to the OP but for anyone else with heated mirror problems, I'm sure someone once said on this forum that the mirror heating only came on when the temperature fell below a certain level. Is that true or not?

Found it: http://www.a2oc.net/forum/showthread.php?8492-Heated-mirrors&p=64904#post64904


http://www.a2oc.net/forum/showthread.php?8492-Heated-mirrors&p=64923#post64923
Click to expand...

Minor correction required here Alan. - The first Quote was from Skipton who has the Winter pack with factory fit heated mirrors.

For your 'true or not' question, I think my comments from those old posts could still be accurate -

If you have retro fit heated mirrors they only turn on with the heated rear screen regardless of temperature.

If you have the winter pack, according to Skipton, the mirrors either automatically switch on below 5 degC, or at any temp with the heated rear screen

Cheers Spike
 
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