Hello everybody,
I have a 2004 stilo MJT 140. Everytime i turn the key on the F11 fuse burns ( 15A ), i disconnected all the sensors/valves related to this fuse (air sensor, egr, preheater box, solenoid and air intake valve ). And it is still blowing it is driving me crazy.

it happened first time when the car was on but not moving, second time it burned after 20 kilometers, 3rd time burned in 500meters. Now it burns everytime i turn the key....
If any of you had the same behavior or any idea i would really appreciate your help.

Thank you!

The owners manual states that fuse F11(15A) is for Secondary Services(Electronic Injection).

yep , i disconnected all sensors/actuators etc.. connected to this fuse. Still blowing ...

For a 15A fuse to blow the instant you turn on the ignition there must be a direct short circuit somewhere.

I'm sure Deckchair will be along shortly to help you diagnose it.

Rather than blowing fuses all the time, simply remove the fuse and connect your meter set on resistance, one lead on downstream side of fuse connection and the other connected to earth and keep disconnecting items downstream of the fuse until the resistance isn't near zero any more

You haven't mentioned the oil level sensor K31 which is fed from F11 so have you checked that one?
Others you have found are pre heater box, solenoids L30 , L36 and L62 and MAF sensor.

If the resistance still shows near zero with all of those disconnected then the supply from fuse to those items is short circuited to earth so check for cable damage, pinched cables, burned insulation or the circuit board on B1 fuse box damaged/ corroded/ warped so disconnect connector D on B1 fusebox and see if zero resistance is still showing, if it is then it's a damaged CB

I also disconnected K31, forgot to mention IT. I will check the wire. What about the connection to T19 going to the connector A pin 68 of M10? What is it supposed to do? Any way to check it without disconnecting the whole connector?
Thank you for helping!

T19 isn't anything to do with F11

T9 feeds F11 and your problem is downstream of F11

Thanks to the RTA i found, the BN wire (from F11) merge with AN wire, which go back to B1 and feeds T19 .

Here is the information i have, might be wrong, i would appreciate if you give me yours.
Thanks you
i52.tinypic. com /2q2pons.jpg

Yes you're right the BN loops back to feed the relay T19 but there is no direct path to earth there, the ECU supplies a reference earth to the T19 relay and you are looking for a problem of a short circuit to battery earth. You could just remove the T19 relay and test if the resistance from the downstream side of F11 to battery earth is still near zero, if it is then the problem is elsewhere

Thanks for the resistance advice, i'll check it tomorow and inform you ASAP.

Hi, news!
i used the meter and i have infinite resistance if i plug it +fuse<->+meter and -fuse<->-meter
If i plug it +fuse<->-meter -fuse<->+meter i have a small resistance. if i check it on items i have almost zero ohms.

Why only in one side? :/

Does anyone know where is the merging point of BN and AN wire?

i used the meter and i have infinite resistance if i plug it +fuse<->+meter and -fuse<->-meter
If i plug it +fuse<->-meter -fuse<->+meter i have a small resistance. if i check it on items i have almost zero ohms.

Sorry I can't work out what you're saying there. What we want is the accurate resistance, fuse removed, from downstream (ie output side) of fuse to battery earth. We know the voltage so if we find out the resistance then we can guess the current and why the fuse is blowing, the resistance might also give a clue as to what component or fault it's likely to be

Then disconnect connector D as described above and check resistance between pin 7 wire color BN and earth, if it's higher then the problem is in the circuit board

Can't help you with the merge point, sensible place would be central to all the components it feeds

Will do it tonight. But i must find a way to keep T9 switched on without connector D.
Thanks

You don't need power on to do a resistance check. Just check resistance downstream of connector D pin 7 to earth and you'll be checking everything up to T19 . If you have near zero ohms then you've narrowed where the problem is

With connector D disconnected and F11 removed there should be no circuit between downstream F11 and earth, if there is then there's a circuit board problem short circuit

Problem solved, a wire was scratching on the body due to vibration. Which slowly caused the shortcircuit, that is why i couldnt see a shortcut on my ohmmeter the contact wasnt good enought for low amperage.
Here is the bug!

Excellent

That looks quite nasty, just as well the fuse was going each time as that's otherwise quite a fire risk

Do you have a picture from further back so we can see where that trouble spot is?

nop no picture, but it is just behind the battery. Between ABS and plastic protection of the battery. Is was scratching by the suspension side.

Ok thanks. Looks like it should be the last time you'll see that problem