Technical Radiator fan circuit

[valeriovanni]

I have a Stilo 1.8 Multiwagon, mid 2003.

The issue is that the radiator fan doesn't start. I try to report here all the data found so far.

I connect Multiecuscan -> actuators
FAN 1 speed: nothing happens
FAN 2 speed: error "unable to execute test"

The second outcome doesn't surprise me, since this circuit seems to have only one speed (see below).

So I tried to look at fuse boxes. I don't have original manual on paper, I downloaded one from Internet named 00_192_STILO_603_81_010_IT_02_11_06_L_LG.pdf.
But it says, about 1.8 (fuse box near battery):
F06 30A FAN 1 speed
F07 50A FAN 2 speed

And it's plain wrong: In F06 there's a 50A, in F07 no fuse. Note: I'm not talking about a missing fuse, there is no connector below. Fuse blades fall into void.
So, can I trust such a pdf?

Then I digged again, and according to https://4cardata.info it seems that the correct scheme for 1.8 and 2.4 is this:

E5020 ENGINE COOLING - WIRING DIAGRAM - Fiat - STILO - eLearn - 4CarData

4cardata.info

It reports a power positive conductor through F06 (50A), and a control positive line through F16 (7.5A).
They both go to a specific ECU for fans, behind radiator, M150.

To M150 go, in addition, a power earth (thick cable) and a control earth from engine ECU.
Then a couple of cables go out from 150 to fan motor.
Rather simple: 2 power cables IN (+ -), 2 control cables, and 2 power cables OUT (+ -).

Mi project was to remove M150, detach connectors and then test
-if power cables carry current
-if control cables carry current
-if I put current on out, does fan start?

But project failed: I removed M150, but there is no connector. Cables go into rubber.
I tried to dig rubber with fingernails, but then I stopped because I felt I was doing mess.
And then I decided put some liquid rubber to repair.

"M150" component is not a simple box as in the picture, it includes cabling. This explains why colors of cables of M150 don't mach with the ones on picture: picture is related to the companions at end of these cable, not at the cables themselves.

So the next step would have been to find end of cabling. But, before, I tried some test with fuses.
I tried to remove F16 (command +), and it was ok. But when I took it out I heard a multiple bell from inside. "ASR failure" "ESP failure".
Does it make sense? I think not... I take out the fuse that sends a positive to FAN ECU, what does ASR and ESP have to do with it?

Then I said "let's try to check the other 7.5A fuses down there. Just hoping that some data was coherent... that the broken fuse a 7.5 one.

So I tried to take off F19... it was ok.
Then I tried F18... still ok, but this time when I took it off the fan started. But not with actuator test, it simply started when I took off the fuse.
And this? What does it mean?

At that time I learned that
-FAN motor is ok
-M150 ECU is ok. It has a line in, a line out, and a trigger one. If fan starts, a trigger is received.

But why taking off a FUSE (of another circuit) should trigger M150?
In pdf manual, F18 is labelled as "+30 electronic injection system". But, as I said, how can I trust that pdf?

 

[aschiuta]

F18 is the +12 volt power supply line of the ECU directly from the battery. When the ignition is on, F16 also supplies other components, not only E150. Hence the ASR, ESP error... F6=50 A goes to M150 and from there it directly supplies the fan motor. Your fan is variable speed. It does not have 2 speeds. The speed command is given by M150. The fan start command and its speed are given by the ECU on pin 14. Put all the fuses in their places. If you want to test then you have to replace the engine temperature sensor with an adjustable resistor. The temperature sensor gives a signal to the ECU and when it reaches the preset threshold, the ECU gives the command to M150 to start the fan.

 

[valeriovanni]

F18 is the +12 volt power supply line of the ECU directly from the battery.

So, taking it off would shut down ECU?
Could it be that M150 turns fan on when it receives no signal from ECU? It would be a smart choice: if no one tells me anything, to stay on the safe side I turn on fan.

When the ignition is on, F16 also supplies other components, not only E150. Hence the ASR, ESP error...

In my pdf F16 is for:
-----------
Impianto iniezione elettronica/Impianto Selespeed
(versioni 2.4 20V)/Centralina elettroventilatore radiatore
(versioni 2.4 20V) (positivo sotto chiave)
-----------
It's in italian, but it doesn't mention ESP or ASR. And radiator fan only for 2.4

And F18 is indicate only for
+30 Impianto iniezione elettronica
(again, no mention to ECU: "iniezione elettronica" means fuel injection)

So, as for FAN 1 speed and FAN 2 speed, it seem to report random data.
Where can I find a reliable description of all fuses? I have other issues, how can I diagnose starting from random data?

F6=50 A goes to M150 and from there it directly supplies the fan motor. Your fan is variable speed. It does not have 2 speeds.. The fan start command and its speed are given by the ECU on pin 14

Ah... I thought that pin 14 was an on/off signal.
This would explain why FAN1 / FAN2 actuators tests fail in Multiecuscan: ECU doesn't have these functions.
So there would be a question for Multiecuscan makers: if an ECU doesn't have a function, why do you insert a related "actuator" program?

Put all the fuses in their places. If you want to test then you have to replace the engine temperature sensor with an adjustable resistor.

I seems a good idea, but perhaps I could try simply to leave engine on.

Perhaps I'm chasing a non existent issue: at the start of my diag there weren't evidence of overheating, I simply connected Multiecuscan and wanted to test fan. But multiecuscan has fake actuators, I saw actuators fail and for that I thought "fan doesn't work".

The idea to check fan came to me because I had just fixed cooling system of my other car (Lancia Lybra). There the issue was real, both fans were broken, but also then (after the replacement) I stumbled on Multiecuscan actuators issue. For that car, FAN 1 speed actuator is written well, FAN 2 speed is written badly. So, in order to be sure that everything worked, I had to leave engine on and reach target temperatures.

And, after everything was ok, I said "Hey, I could take a look on Stilo too with Multiecuscan"
So I passed from 1 badly written actuator to 2 ones.

 

[valeriovanni]

Non existent issue
I simply let the engine go to 90°, then I stopped and left it idling 2 minutes. I saw no reaction, so I increased engine speed for a minute.
I went out, and the fan was rotating. After a bit it reduced its speed, so it seems everything is working.

During M150 dismount, I found a dangling connector.
It has no relation with M150.

The cable comes from the center (near engine hood lock), passes near M150 and then dangles down into void.
I found no compatible mate within cable reach.

The colors are black and blue, this photo is overexposed. I still haven't checked for current on it since I was focused on diagnosing fan.

I also tried to search in 4cardata about other circuits, with the hope to find some blue/black connector, but it's like searching a needle in a haystack.