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Marty
Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53774
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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how to wire a k40 switch to a 1998 Mercedes slk 230 compressor

Customer Question

how to wire a k40 switch to a 1998 Mercedes slk 230 compressor
Submitted: 6 years ago.
Category: Mercedes
Expert:  Marty replied 6 years ago.

eurotec :

Hi, are you referring to the K40 relay?

eurotec :

Which plug did you take apart on the relay?

Customer:

Yes , I had to replace the relay and did not mark the wires when I took it off and not sure how to wire it

Customer:

What wires go on what side

eurotec :

The wires can only be installed in one position unless you removed them from the plugs.

eurotec :

Full Size Image

eurotec :

Is that the relay you replaced?

Customer:

I did I had to relace the whole switch can you send a wiring diagram

eurotec :

I am not following you. The plugs can only plug in one way.

Customer:

There is one plug and 4 wires i know where the plug goes but there is 2 studs and 4 wires on top of the relay not sure which wires go on what stud

eurotec :

That does not sound like the K40 relay. Where is this part located?

Customer:

on the passanger top fender

eurotec :

And it looks like the picture I gave you?

Customer:

no

eurotec :

I gave you the K40 relay.

eurotec :

What are you working on?

Customer:

I relaced the fuel pump and was told it was the switch on the right passanger fender

eurotec :

Can you give me the part number of the part you are working on?

eurotec :

The K40 relay that I showed you is the fuel pump relay.

Customer:

will have to call the store one moment

eurotec :

ok

Customer:

one moment Please calling the store have not picked the part up yet Thanks

Customer: (NNN) NNN-NNNN/p>
eurotec :

That is your battery cut off relay.

eurotec :

That is not your fuel pump relay.

Customer:

does that switch have anything to do with the fuel pump and if not what do we need and also how do I wire that one up

eurotec :

No it does not

eurotec :

Full Size Image

eurotec :

Click on the image

eurotec :

Those big wires all have power on them. I hope the battery is disconnected.

Customer:

so is it the fuel pump relay what I need.... after we put the new fuel pump back on it still won't start

eurotec :

Possibly, if your fuel pump is not running it could be a bad K40 relay.

Customer:

where is the k 40 relay located and what is the part number

eurotec :

The K40 is inside the module box right next to the relay you disconnected.

eurotec :

210 540 00 72, Relay

Customer:

Thank You So Much

eurotec :

You're welcome

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