[deepvo]

Hello, I am a newbie and hope I am posting in the right forum.
I have a 2009 C300 sport. The check engine light was on so I took it to the dealer and they said the secondary air pump and relay needed to be changed. They wanted $1800 for this work. I sourced a new secondary air pump and changed it quite easily. My problem is that I do not know which relay controls the secondary air pump. Any one able to help?

 

[rudeney]

You should be posting in the W204 form as you will likely get better information related to your car. However, I did check and it's relay "P", on the front SAM (engine compartment fuse panel). It's next to fuse #32 .

 

[deepvo]

Hello and Thank you for your reply. I did realize that I should be posting on W204 forum and did post the same message on that forum (about 1/2 an hour after posting on W203 Forum).
Would you happen to have a diagram that shows the letters on the relay switches. The only diagrams that I can find have the numbers on the fuses but no letters on the relay switches. If you have this diagram, I would really appreciate a copy for future use. Thank you, once again.

 

[rudeney]

Here you go:

http://benzbits.com/W204/FrontSAMFusePanel.pdf

 

[deepvo]

Thank you very much. You are a god send!
The problem is fixed now.
Saved a ton of money.