Ok so what else is controlled by the Epb unit does it do things like steering angle? traction control?
It get’s power from all 3 feeds but the iid tool is telling me it’s the switch but I now have the traction control coming on when I go round a roundabout
So could it be the unit that is faulty not the switch?

The problem is that the EPB module (which controls the EPB system) is connected to the switch and also to the CANBUS. So you can get cascade failures caused by something else throwing a fit.

For example, the EPB module will ask the ABS system to apply the main brakes if the switch is pulled and held at speeds above 10km/h - so called "dynamic apply mode". So a problem in either the EPB, the switch or the ABS system could throw an error up. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

If I could sort out which wires in the switch are connected when not operating I might be able to bypass it and see if that stops the fault from showing up

You may as well clean the inside of the epb switch (it’s like a tv remote control) or get a second hand one

jk3528 wrote:

If I could sort out which wires in the switch are connected when not operating I might be able to bypass it and see if that stops the fault from showing up

Assuming you have an L320, the workshop manual is here: https://www.mediafire.com/file/yunzrqm47py4pww/RRSL320WSM2006.pdf

There is a section on the EPB and the wiring layout is shown in the wiring diagram section.

Good luck.  2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Yes it’s a 2006 l320 2.7v6
Thanks

The other thing that could be initiating the traction control is a sticky front left calliper (seeing as its a roundabout). Happened to me, took me a while to work it out.