E-Class (W211) 2003-2009

Side view mirror heater

Old Oct 24, 2018 | 08:26 PM
  #1  
Pitek's Avatar
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From: Ontario, Canada
06 MB E350 4Matic Sedan, 08 MB S550 4Matic Sedan
Question Side view mirror heater

Hi everyone,

The passenger (right) side view mirror heater does not work. However, it adjusts its position.

The rear window defogger works. The left side view mirror fully works (adjusts its position and heats up).

I checked the green 30 Amp fuses (left and right side mirrors) in the fuse box. They are fine.
I checked the voltage on the two tiny wires at the back of the mirror glass after tilting it down. The voltmeter reads 5.5 V - 5.6 V when the car runs in idle.

Why is it not heating up now? It worked fine last winter. What is wrong?

Thank you,
Pitek
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Old Oct 25, 2018 | 09:37 AM
  #2  
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ot1
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Joined: Apr 2007
Posts: 633
Likes: 48
From: USA
2006 E320 CDI
Originally Posted by Pitek
Hi everyone,

The passenger (right) side view mirror heater does not work. However, it adjusts its position.

The rear window defogger works. The left side view mirror fully works (adjusts its position and heats up).

I checked the green 30 Amp fuses (left and right side mirrors) in the fuse box. They are fine.
I checked the voltage on the two tiny wires at the back of the mirror glass after tilting it down. The voltmeter reads 5.5 V - 5.6 V when the car runs in idle.

Why is it not heating up now? It worked fine last winter. What is wrong?

Thank you,
Pitek
disconnect the two wires for the heater and measure the resistance, and post back your reading. Measure the other side and you will see that it has 12v. You can measure its resistance for comparison. Since you likely will be needed new glass, somebody here said there is european curved glass available from mercedes which will give a wider view.

Last edited by ot1; Oct 25, 2018 at 09:41 AM.
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Old Oct 25, 2018 | 11:28 PM
  #3  
Pitek's Avatar
Thread Starter
Member
 
Joined: May 2016
Posts: 130
Likes: 23
From: Ontario, Canada
06 MB E350 4Matic Sedan, 08 MB S550 4Matic Sedan
Originally Posted by ot1

disconnect the two wires for the heater and measure the resistance, and post back your reading. Measure the other side and you will see that it has 12v. You can measure its resistance for comparison. Since you likely will be needed new glass, somebody here said there is european curved glass available from mercedes which will give a wider view.

Resistance reading

After disconnecting and removing the mirror glass I checked the resistance. It read 98.6 Ohms. Also, I checked the voltage on the two hanging from the mirror case wires. It read 12.6 V on the idly running motor.
Finally, I checked the continuity on the two tiny terminals on the back of the mirror glass. No beep = no continuity.
I have not checked the left (driver's side) mirror for resistance yet. It got quickly so dark after work. I will do it tomorrow.

So, what is the verdict so far? Anyone?

Thank you,
Pitek
Reply
Old Oct 25, 2018 | 11:37 PM
  #4  
ot1's Avatar
ot1
Super Member
 
Joined: Apr 2007
Posts: 633
Likes: 48
From: USA
2006 E320 CDI
Originally Posted by Pitek

Resistance reading

After disconnecting and removing the mirror glass I checked the resistance. It read 98.6 Ohms. Also, I checked the voltage on the two hanging from the mirror case wires. It read 12.6 V on the idly running motor.
Finally, I checked the continuity on the two tiny terminals on the back of the mirror glass. No beep = no continuity.
I have not checked the left (driver's side) mirror for resistance yet. It got quickly so dark after work. I will do it tomorrow.

So, what is the verdict so far? Anyone?

Thank you,
Pitek
that mirror has about a 1/2watt of heat going through it, you should have close to 10 ohms resistance. That would give you about 14 watts of heat.
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