How many fuses are in a Mercedes K40 relay module?
Remove the four phillips screws and the cover will pop off. Here you can see the module sort of tucked under a wiring harness. The relay module has five plugs (all different sizes so you won’t mess up when you reconnect them!), five 15 amp fuses, and one large red 40 amp fuse.
Where is the K40 relay on my 98 slk230?
Just searched the net for a k40 relay for my 98 slk230. I found what appears to be a k40 relay, but not the k40 relay module described in previous posts. Both part suppliers said it is located “right front under hood”, but I don’t see anything that looks like the picture on their site.
When does the K40 send power to the starter?
I think that the K40 should send power to the fuel pump for a few seconds when the ignition is turned on. Then, and only then, the K40 should send power to the starter when the key is turned. Is this correct? If it is correct then the no cranking symptom is a result of the k40 not supplying power to the fuel pump?
How many amps does a Mercedes relay module have?
The relay module has five plugs (all different sizes so you won’t mess up when you reconnect them!), five 15 amp fuses, and one large red 40 amp fuse.
Why did my Mercedes-Benz K40 relay module fail?
But it does sound like the K40 – although failures were rare on the facelift models. The fault was the K40 relay module, as suspected. I replaced the whole module, but it was probably a failure of the relay controlling the fuel pump (2nd from left when viewed from the side with the fuses).
Where is the K40 relay on a Mercedes SLK?
The K40 relay is located in the control module box, under the hood. In left-hand-drive R170 SLKs, this box is near the exhaust manifold. A heat shield and a blower motor keep the electronics in the box cool.
What causes the K40 overload protection relay to malfunction?
The notorious K40 overload protection unit is a well-known cause of starting, idling, and engine stumbling problems. This unit provides voltage to the control modules and electrical components, including the fuel pump, electric air pump, and horn. When the K40 malfunctions, these components don’t get their required…
How can I repair my Mercedes SLK 230 overload protection relay?
A brass clip (green arrow) keeps the K40 in place. Pressing it outward sets the K40 free. Pull the plugs off the K40 and remove it from the car. A skinny flathead screwdriver can be used to pry the relay board out of the case. Check the relay side of the board for obvious problems: charred or loose connections, etc.
Where is the F5 fuse on a K40?
On regular occasions the car will cut out, everytime its because the F5 fuse, one of the blue 15 amp fuses located on what is commonly known as the K40 relay module, has blown.
Why did Mercedes use a relay module instead of a block?
For some reason, Mercedes decided to use a complex and expensive relay module instead of a traditional block of separate relays. Normally if a relay fails, only that component will cease operation. In this case, the main power feed solder joint failed, cutting power from all accessories run by that module
Where is the relay module located on a Mercedes slk230?
*Remember to always disconnect the negative battery cable prior to any kind of electrical service. To confirm my diagnosis, I removed the relay module, located inside an electrical box on the passenger side of the engine bay (for left hand drive vehicles. Right hand drive vehicles will be opposite).
What was the fault of the K40 fuel pump?
Most people believe that there must be some out there somewhere, but nobody has yet been able to prove their existence. The fault was the K40 relay module, as suspected. I replaced the whole module, but it was probably a failure of the relay controlling the fuel pump (2nd from left when viewed from the side with the fuses).
What does the K40 relay module do on a SLK320?
K40 relay module. What exactly does it do? My SLK320 does not crank when I turn the key, and there is also no power reaching the fuel pump. The battery is absolutely fine.
Most people believe that there must be some out there somewhere, but nobody has yet been able to prove their existence. The fault was the K40 relay module, as suspected. I replaced the whole module, but it was probably a failure of the relay controlling the fuel pump (2nd from left when viewed from the side with the fuses).
K40 relay module. What exactly does it do? My SLK320 does not crank when I turn the key, and there is also no power reaching the fuel pump. The battery is absolutely fine.
I think that the K40 should send power to the fuel pump for a few seconds when the ignition is turned on. Then, and only then, the K40 should send power to the starter when the key is turned. Is this correct? If it is correct then the no cranking symptom is a result of the k40 not supplying power to the fuel pump?