My old Mongoose cable for SDD had packed in and the new one I had ordered arrived today so I decided to dig out SDD and give that a whirl rather than my IID tool and have a look in the software. The RBM (Running Board Module) is listed as an ECU on the list of ECU’s but unfortunately its status is “Optional Module Not Responding/Fitted”.

The IID tool lists the ECU but pulls no data from it. Swapping the ECU out makes no difference either so it had to be an issue on the car.

I’m spending much more time on these then I should be but the fact they’re fitted and isn’t working is really annoying me.

Keep going I know how you feel if they weren't there fine but as they are they need to work. It is not that it is disabled in the control module software?or the BCM ?

Try this David I had the same issue as you nothing at the switch but power was good so today I was recalibrating things so manually set the normal height on the suspension to as low as I could then went round and reset all four corners at access normal and extended whilst I was at it I recalibrated the steering now once I had done this I tried holding the button for the steps position one then two got the two flashes and the steps are working again.
I think sometimes the train response sends a disabling signal to the steps ecu and thats why it is just dead and by me recalibrating the heights and steering it cleared it somehow and now they work worth a try when you get bored with the 5.0 l