I've been a long time trying to get some sound in the ol'girl (RR) but no joy at this stage.
I wriggle the wires around the DSP Amp and hay presto i have sound but no volume control and only right with sound.

So i purchased another Amp ( a known good one) and fitted just on the side, just in case I had no sound either!
That Amp worked like the first one for two or three minutes, after all this (its doing my head in) i thought it might be i Mute mode but couldn't find it on the steering wheel controls (no mute or Mode button) the I read here that if buttons don't work or stuck it could play havic with the Audio.

So I'm trying to find out what is the rotary coupling, this unit seem to control the steering wheel buttons is this correct?

The rotary coupling is the 'clock spring' behind the steering wheel, the switches work on a resistive ladder principle (voltage divider) so you will get a different voltage output dependent upon which switch is pressed. Any poor or broken connection will obviously affect the output and therefore the intended action.

Thanks for the reply Phoenix, does this mean if there is bad contacts or broken buttons it could effect the sound system?
In order to R&R rotary coupling you wold have to take off steering wheel?

I've been trying to get the sound system to function for a long time with no success and I think the RC has a lot to do with it!

Using the buttons on the dash should eliminate the steering wheel buttons…. To a large extent… not sure what will happen if they are connecting and shouldn’t be.

Don’t forget that you have a DSP which acts as a crossover for the speakers and the BM54 radio unit, which actually contains the amp… both can be affected by water damage or corrosion around the connections.

Baris on here used to repair such units, but not sure he’s been on for some time.

I think the steering wheel coupler can get cracks in its connection too.

 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport

Yeah, that's what I was asking about . The DSP amp has been working but I have only the left side working and no volume control on the headunit. This is why I'm heading down the steering wheel buttons channel
Do you know if all L322's have a mute button on the steering wheel?

To eliminate the steering wheel / clock spring, you could just disconnect it on the steering column side for testing. If no change (probably a battery disconnect, just to be sure) then it's not the steering wheel buttons or clock spring and you can look elsewhere.

Thank you, I went out to the Range Rover this morning went to start, dead battery I said golly gosh and went for the battery charger so I’m guessing battery drained overnight Was either caused bye the rotary Coupler or the DSP amp.

I will pull the steering column apart all the wires on the Rotary Coupler and see what happens, report back soon.

Oh, it’s 10am on a beautiful day in Tasmania, I’m guessing it’s somewhere near night fall for you guys.

Have you checked the head unit volume control (same as the on / off button) ?.
As I can turn mine on & off, but turning the same button to increase or decrease the volume doesn't always work. This gives the impression that the unit has failed i.e no sound.

Although I can operate the volume back up or down by the steering wheel controls. At some time I need to replace the head unit.

That’s just what I didn’t want to hear 😕 I will have a look at the volume pot on headunit in the morning, but for now I’ve put her on a trickle charger, I’m not sure where the power drain is coming from.
I have to do some checking with the rotary coupler and windowscreen in morning too… there so much that can go wrong or fail on the L322’s 🇦🇺