a6 c7 3.0 cooling fans runing when car off

[Crasher]

What is the VIN and prod me tomorrow?

[Sloppy]

what is the vin and prod me tomorrow?

wauzzz4gxdn102601

[Crasher]

The way I look at the layout is yours uses the layout from current track 254 to 259 so on the red green at 254 that is ignition live and at 255 is the ECU signal so I would start by checking the junctions shown T4bf and T5 for corrosion and continuity. I have emailed you the full engine current flow diagrams.

Radiator fan control unit, Engine control unit, Radiator fan control unit 2

J293

-

Radiator fan control unit

J623

-

Engine control unit

J671

-

Radiator fan control unit 2

T4bf

-

4-pin connector, near radiator fan

T4bg

-

4-pin connector, near radiator fan

T5

-

5-pin connector, central in plenum chamber, black

T105

-

105-pin connector, black

V7

-

Radiator fan

V177

-

Radiator fan 2

685

-

Earth point 1 at front of right longitudinal member

K21

-

Connection 1, in radiator fan wiring harness

*

-

Hot country version

*2

-

Only models with trailer socket

*3

-

Only models with Tiptronic

[Sloppy]

The way I look at the layout is yours uses the layout from current track 254 to 259 so on the red green at 254 that is ignition live and at 255 is the ECU signal so I would start by checking the junctions shown T4bf and T5 for corrosion and continuity. I have emailed you the full engine current flow diagrams.

Radiator fan control unit, Engine control unit, Radiator fan control unit 2

J293

-

Radiator fan control unit

J623

-

Engine control unit

J671

-

Radiator fan control unit 2

T4bf

-

4-pin connector, near radiator fan

T4bg

-

4-pin connector, near radiator fan

T5

-

5-pin connector, central in plenum chamber, black

T105

-

105-pin connector, black

V7

-

Radiator fan

V177

-

Radiator fan 2

685

-

Earth point 1 at front of right longitudinal member

K21

-

Connection 1, in radiator fan wiring harness

*

-

Hot country version

*2

-

Only models with trailer socket

*3

-

Only models with Tiptronic

Thankyou for the diagram, ive checked continuity from the ecu pins (t105/48/49) and the powers back to connector T4bg, i was hoping one of the ecu wires was faulty (hecne the full power mode) but everything checks out fine and after considering the fans work fine when the car is 'on' this does make sense,

one thing that occurred to me today is perhaps when the car 'goes to sleep' the ecu is missing a live which should be still supplying it when in this mode, with this live missing the fans then have no signal from the ecu and go into full on mode? that would make sense?

I might check pin outs on the ecu for power when the car is shut down, will have to see how many permanent lives its should receive when its asleep and what pins. you dont happen to have any idea which pins should receive power when the car is off.