As I wrote in previous post, I am having an issue with glow plugs on my 2008 E320 Mercedes Benz Bluetec.
Getting a warning about glow plug/glow plug controller on my dash board, I decide to replace the controller and at the same time check the conditions of the glow plugs. Following the glow plug number 1-6 on the female connector from the controller,I found the number 5 as a bad GP.
Now I don't know how are the GP sequence numbers in the engine. How are they numerically located in the engine cylinder head looking the engine from the front of the car?
Also I removed one GP to check the part number in order to buy the correct plug and found all these numbers engraved on it:

CZ 302 7V K72 MK
A 001 159 57 01
NGK

It is a 8 mm Thread.


The new controller is a Beru with Made in Germany engraved on it but the cardboard box says Made in Portugal. After installed and take the car for a drive the glow plug warning went away But I still wanting to replace the bad GP.
Please let me know how to locate the #5 GP.
Thanks

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Nyck - TX - USA