Case Puma Isobus socket not powering screen

[JonL]

I have 2 Case Puma tractors and a kverneland fert spreader running through a tellus isobus screen.
On one of the tractors I can plug fert spreader into rear, plug screen into rear pillar isobus socket and away we go.
On the other I connect up using same cables but get nothing, no power to the screen. There is power to the cab socket.
We’ve tried tracing wire and checking relays etc but it’s not easy!
Any ideas please?

 

[Will 1594]

Johnathon , having similar issues have you had to switch any thing out in tractor auto steer etc ,

 

[JonL]

The only thing that gets changed is swapping auto steer receiver and nav controller between tractors

 

[Robt]

If it’s a retro fit loom on either then the rear retro fit iso socket is powered by an ignition/switched live? This is normally as simple as plugging into an existing cobo in the cab. I’d start there and work backward

 

[JonL]

If it’s a retro fit loom on either then the rear retro fit iso socket is powered by an ignition/switched live? This is normally as simple as plugging into an existing cobo in the cab. I’d start there and work backward

Both are factory fit

 

[Robt]

Ok, check where you have got power and work forward!