640d Mirror heating not working???

[Dez335]

My 14 plate 640d has suddenly decided the heated mirror doesn't want to work?

Has this been known before? common etc.

3rd party warranty from when i bought car and will only pay for 1 hour invest with BMW. So would like to be armed with info of what it could be!

Thanks a no longer 335 owner..

[Charlie Croker mk2]

If the other mirror is still working ? then its likely to be just the glass itself , I suppose the connections inside the housing could be corroded due to jet washing .

[Ninja59]

Nope. Outside temperature I bet you is making them not turn on at full temp

Ultimately it leads to them being fairly "useless" in light condensation conditions as there is no manual override and the car won't turn them on to full temperature.

"Mirror heating is switched on from terminal 15 ON. The heater output is controlled automatically and depends, for example, on the ambient temperature, wiper operation and switch position of driving experience switch. The BDC control unit or FEM control unit or the JBE control unit evaluates the corresponding input signals and adjusts the intensity of the mirror heating."

https://www.newtis.info/tisv2/a/en/f06-640d-cou_20...

They are bloody expensive though - just the mirror glass is about £320.

[Dez335]

Bmw parts cheap as ever! One side cleared other didn't. The temp issue i found but discounted as one cleared. Perhaps i should wait for some cooler weather!

[clockworks]

If it is the glass, are they really that expensive? I bought a pattern part on eBay a few years ago for my Z4, cost me about £20, and took a few minutes to fit.

I wasn't expecting much at that price, but it looked pretty much identical to the remains of the old glass, which had fallen out of the housing on my driveway. It worked properly, too.

[Dez335]

the glass from BMW is £320!!!!

I tried them again this morning the right one seemed to clear pretty quick and the left one just took few mins more (May of been just evaporation of the dew)

[Ninja59]

clockworks said:

If it is the glass, are they really that expensive? I bought a pattern part on eBay a few years ago for my Z4, cost me about £20, and took a few minutes to fit.

I wasn't expecting much at that price, but it looked pretty much identical to the remains of the old glass, which had fallen out of the housing on my driveway. It worked properly, too.

Automatic dimming and electrically heated both of which make them pricey...

Having had one broken, it raised a few eyebrows at the cost on the face of it is a "simple piece of mirror glass".

But once it had cracked it showed why it is so expensive the as numerous layers inside including I presume the ability to dim is driven by a liquid layer.

Techs do not like removing them for exactly the above reason...fragile, easy to damage and cost a fortune to replace.

[aeropilot]

Dez335 said:

I tried them again this morning the right one seemed to clear pretty quick and the left one just took few mins more (May of been just evaporation of the dew)

Interesting, as I've found that on my current BMW (and on previous one) the left clears quicker than the right, in the same way that the left side of the screen clears quicker than the right, which I've always put down to the fact that many things on RHD BMW's are not swapped from LHD setup, due to cost and the left mirrors and screen are set to quicker clear for LHD setup. There's a few other things that BMW don't change on RHD cars as well.