Intermediate light switch issue

[pls1]

Yet another post about 3 way light switch wiring!

I've read quite a few posts but I have an odd one which still can't make head nor tail of despite checking & double checking wiring diagrams.

I have 2 x 2 way switches at each end with intermediate in the middle. With the current wiring the intermediate doesn't turn the light on or off but both the 2 ways at each end do (with the intermediate in either position).

Wiring as follows:

2 way switches (at each end)
COM = BLACK
L1 = BROWN
L2 = GREY

Intermediate
TOP
L1 = BLACK
L2 =GREY
BOTTOM
L1 = BLACK
L2 - GREY

I have checked the continuity of the intermediate switch to ensure it does X or || so I know this is working.
Pics of both 2 ways and finally the 3 way. Just to add the Live & Switched Live are connected in a Wago box in the ceiling rather than at the switch.

Initially I had the Brown & Black reversed in the 2 way switches, so COM was BROWN & L1 was BLACK but all the switches didn't work as expected in certain on/off configurations. Swapping the connections means the 2 ways both work as expected but now the intermediate doesn't.

 

[bernardgreen]

It looks like you have at the 2 Way switched Black in the Com and Grey and Brown in L1 and L2. These are the strappers that run from switch to switch

Based on that It is most likely that the wiring at the intermediate should be :-

The strappers ( Grey and Brown ) need to be in L! and L2 terminals at the intermediate and the wires from the two Com ( Blacks ) need to be joined in a terminal block.

 

[333rocky333]

Intermediates need to be in the 2 strapper lines to work
In your case L1 and L2
If you link across the same colours at the intermediate without the switch and get the Two 2 way working then its a straightforward fit of the intermediate front

 

[pls1]

It looks like you have at the 2 Way switched Black in the Com and Grey and Brown in L1 and L2. These are the strappers that run from switch to switch

Based on that It is most likely that the wiring at the intermediate should be :-

The strappers ( Grey and Brown ) need to be in L! and L2 terminals at the intermediate and the wires from the two Com ( Blacks ) need to be joined in a terminal block.

Thanks, that was indeed the issue.
I couldn’t remember how the live & S/W live were connected to COM, L1 & L2 in the Wago as it’s now inaccessible.

Joined the COM (blacks) in the back of the intermediate switch & connected brown to L1 and grey to L2 which sorted it.