Do it yourself
Frequently asked questions about cars and motorcycles
Car tutorial (Do it yourself) Motorcycle tutorial (Do it yourself) Frequently Asked Questions

Replacing K40 Relay in Engine Compartment Fuse Box

Model: Mercedes Classe E W210 - Years 1995-2002
Part: Checks and maintenance

If you are experiencing engine starting issues and warning lights on the dashboard, one possible cause is a faulty K40 relay located in the fuse box in the engine compartment, on the passenger side, near the strut tower. Once you remove the cover, you can easily identify this relay; pull it out from its socket and insert the new one. If the problem does not resolve, proceed to the next step: remove the fuse box and check the solder joints on the underlying circuit board, and re-solder them if necessary.

Updated on 10 February 2026 by ScegliAuto

Video tutorial

Related tutorials

Where Are the Relays in the Mercedes E-Class?
Where Are the Relays in the Mercedes E-Class?
Mercedes Classe E (1995-2002 / W210) In this video, you can see where the relays are located in the Mercedes E-Class W210, useful in case you need to check the relay of a malfunctioning …
Where to Find the Relays in the Mercedes E-Class?
Where to Find the Relays in the Mercedes E-Class?
Mercedes Classe E (2009-2016 / W212) In this video, you can see where the relays are located in the Mercedes E-Class, useful if you want to check the relay of a malfunctioning device. As…
Fuel Pump Fuse Relay Replacement
Fuel Pump Fuse Relay Replacement
Mercedes Classe E (2002-2009 / W211) To replace the fuel pump fuse relay, open the trunk and remove the plastic panel on the left side wall. This allows you to see the cover of the relay…

Other guides you may be interested in

How to Open the Bonnet on the Lancia Y

To open the bonnet on this vehicle, follow these simple instructions: first, open the driver's door and locate the lever positioned just below the dashboard, marked with an image of the vehicle with the bonnet open. Pull this lever towards you until you hear a "click" indicating the bonnet is released. Next, exit the cabin and stand in front of the bonnet to disengage the safety catch and complete the opening. To do this, slightly lift the bonnet, locate the yellow lever underneath, and pull it to the left to fully release and open the bonnet.

Watch the video!


by ScegliAuto

More videos