witness of pre-heating remains lit after starting.

[basamir]

yeh, i was found this diagram but i had doubts about site of relays 5 and 8, if not is this there is possibility to control and verify operating condition of this relay or it should be replaced straightforwardly?

 

[grober]

Without an internal circuit diagram and an understanding of how it operates its going to be difficult to test. Its called a "timer" relay so I guess the internal timer circuit is not switching off after the appropriate time and the glow plugs remain on. The simple solution is direct replacement. Its about £50 plus vat plus carriage from here. http://www.mercedes-benz-parts.co.uk/home/

 

[basamir]

Hi all,
Yesterday i was found the relay of pre-heating it's located below the container of glass water, so it's like a black box with a big connector with 5 pins (5 plugs) and a small one with only 2 pins (the witness in panel inside the car).
I was disconnected the small one and the led still lit all time.
I dont know if i can do something to repar this relay cause i m electonicien but without diagrams it's like a MI 4
Where can i find one please?

 

[grober]

The Mercedes circuit diagrams show it to be a solid state device not a conventional relay with contacts coil etc so probably impossible to field repair.