Heated Mirrors

C

creepy coupe

Guest
Can someone please advise me how they work, the handbook states "automatic" so are they on all the time, or below a set temperature?

The cars a 1998 SLK 230

Many thanks
 
Last edited by a moderator:

roadhog

Senior Member
Joined
Aug 2, 2007
Messages
1,616
Reaction score
2
Location
Sunny Norfolk
Your Mercedes
W124 300D x2, C124 300
On any of my cars they come on when you select the heated rear screen.
 
OP
C

creepy coupe

Guest
  • Thread Starter
  • Thread starter
  • #3
On any of my cars they come on when you select the heated rear screen.


The same here, all except for a TT I owned and they were on all the time.
 

matthewm1965

Senior Member
Joined
Jul 11, 2009
Messages
210
Reaction score
0
Location
Durham
Your Mercedes
1999 W220 S500L, Toyota Supra Mkiv, 1970 Triumph GT6
Not sure about the Mercedes system as I have not seen it working yet ! But when I had the Rover 800, they were on all the time, summer & winter. The ones on the Vectra came on with the heated rear window.
 
OP
C

creepy coupe

Guest
  • Thread Starter
  • Thread starter
  • #5
Someone has suggested they come on when you use the screen demist function?
 

Blobcat

Moderator
Joined
Feb 8, 2006
Messages
30,113
Reaction score
15,492
Location
Grange Moor
Your Mercedes
R171 SLK280, Smart R451, Land Rover 110 County SW, 997 C2S, R1250 GSA TE 40th, CBR600FP
Some cars it comes on with the demist, others (later ones) when it drops below 5'C. Today I had the first frost on mine, however as my screen is very clean inside and out it didn't take very long at all for the demister to clear it and the mirrors.
 
OP
C

creepy coupe

Guest
  • Thread Starter
  • Thread starter
  • #7
Some cars it comes on with the demist, others (later ones) when it drops below 5'C. Today I had the first frost on mine, however as my screen is very clean inside and out it didn't take very long at all for the demister to clear it and the mirrors.

Thanks for that Bobcat, I was hoping for a reply like that :D
 

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
332
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
The AIR temp and start up circuits come into this, and all CAN BUS driven. The mirror heater is controlled from the door control ECU and is switched on and off by the outside air temp sensor, they are switched on at temps below 5c and switched off at 10c and above. If the widow is opened,then the mirror is switched off, to save energy.

They also come on automatically with the heated rear window
 

Dec

Senior Member
Joined
Nov 30, 2005
Messages
3,300
Reaction score
3
Location
Ireland.
Your Mercedes
W202
The best way of knowing under what conditions the come on is by touching the mirror with the back of your fingers, you will feel the heat in the glass after about 30 seconds.

Dec
 

whitenemesis

Senior Member
Joined
Dec 21, 2006
Messages
17,978
Reaction score
27
Your Mercedes
CLS55 AMG '05
As Malcolm says (on mine at least) mirrors come on with the ignition at temps below 5c and stay on to prevent misting up in foggy weather etc..
 
OP
C

creepy coupe

Guest
  • Thread Starter
  • Thread starter
  • #11
I diid have the rear screen on for about 10 mins last night, but didn't notice the glass feeling any warmer

I'll try some other senarios tonight.
 
Last edited by a moderator:

Dec

Senior Member
Joined
Nov 30, 2005
Messages
3,300
Reaction score
3
Location
Ireland.
Your Mercedes
W202
I have never been able to feel the heat in the back window while the heater is on, I think it is a much slower affair, you can really only tell if it is working when it clears the mist, the mirror on the other hand becomes quite warm to the touch.

Dec
 

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
332
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
I have never been able to feel the heat in the back window while the heater is on, I think it is a much slower affair, you can really only tell if it is working when it clears the mist, the mirror on the other hand becomes quite warm to the touch.

Dec

Purely on mass Dec, the mirror is so small compared to the back window plus the mirror is floating, and the window is attached to the body of the card
 

whitenemesis

Senior Member
Joined
Dec 21, 2006
Messages
17,978
Reaction score
27
Your Mercedes
CLS55 AMG '05
The heater must still raise the temp of the glass above the dew point to drive off the moisture.

A colleague had a rear window explode due to a fault in the heater where it didn't auto switch off
 

Lisa Jayne

Senior Member
Joined
Feb 7, 2009
Messages
309
Reaction score
1
Age
52
Location
Ashford, Kent
Your Mercedes
1998 SLK 230K & 2003 ML270 CDI Inspiration
Gave my wing mirrors a touchy feely when I got home and they were both definately warm, outside temp 14.5, no rear screen demister on, so I would think that they are on all the time ;)
 

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
332
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
Gave my wing mirrors a touchy feely when I got home and they were both definately warm, outside temp 14.5, no rear screen demister on, so I would think that they are on all the time ;)

No they are not on all the time, they work as in my post 8 they may feel warm but that is only heat that has worked its way up into the housing
 

Lisa Jayne

Senior Member
Joined
Feb 7, 2009
Messages
309
Reaction score
1
Age
52
Location
Ashford, Kent
Your Mercedes
1998 SLK 230K & 2003 ML270 CDI Inspiration
No they are not on all the time, they work as in my post 8 they may feel warm but that is only heat that has worked its way up into the housing

Well my passenger side one was almost hot to the touch so just guessed that the heating was on sorry :roll:
 

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
332
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
Well my passenger side one was almost hot to the touch so just guessed that the heating was on sorry :roll:

Maybe it is stuck on or something,,,we have had this question up many times and it has never been answered exactly,,this morning I spent an hour checking on how they work,,and it is the same for all cars.

I will look, at the 170 specifiably later today
 

whitenemesis

Senior Member
Joined
Dec 21, 2006
Messages
17,978
Reaction score
27
Your Mercedes
CLS55 AMG '05
I must correct myself. The temperature I quote was incorrect, should be switched on at temp below 15c and off at temp above 19c :Oops::Oops:
 
Last edited:

television

Always remembered RIP
Joined
Mar 14, 2005
Messages
164,073
Reaction score
332
Age
86
Location
Daventry
Your Mercedes
2002 SL500, 216 CL500, all fully loaded
I must correct myself. The temperature I quote was incorrect, should be switched on at temp below 15c and off at temp above 19c :Oops::Oops:

OK so we do have differences in our cars with the on and off temp,,as I said mine are on at 5c and of at 10c,,the main thing is that we now know how they are turned on and off, even if the temps vary,, just shows Peter how much colder your car is than mine:D

I am pleased you found it in the end:D
 

Stop looking for the Best Garage!! We are here and have the best advanced solutions for you, at Competitive prices. Put us to test with any issue you may have.
Top Bottom