One way, two gang light switch - only one lamp works

[Norwichcitizen]

My old dimmer switch broke so I bought a new one thinking I could easily change it myself. My big mistake was failing to take note of which wire went where and now I can get just one lamp working at a time. If you look at my photo you will see there are three wires, one black, one grey and one brown. I THINK the grey one might be the live one as it was swapping this from one gang to the other that swapped which room has a working light in it. Anyway, I did notice that there were two wires in one gang (at L1 and Com) and one wire in the other (at L1). There was also a short brown wire sticking out of Com on the second gang but I don't know if this was connected to anything or not, presumably so. I have attempted to show this by holding the old switch up above the new one in the photo.

Anyone able to help please? Thank you.

 

[flameport]

The short brown wire links both COM terminals together.

 

[Norwichcitizen]

The short brown wire links both COM terminals together.

Thank you.

Any idea where the other three wires should go please?

 

[Taylortwocities]

There are 101 ways to wire up lights. Guessing is not the best way forward. To do it properly you need a multimeter.

But if I had wired it up (I didn't) then brown to COM with that link wire going to the other COM (that should be your live feed in). black wire on one of the L1 terminals and grey wire on the other L1.

EDIT. you need to do some work insulating the black wire with the tape on it. There's a bare wire in there, that i can see. If that touches the metal box, then BANG!

 

[Norwichcitizen]

There are 101 ways to wire up lights. Guessing is not the best way forward. To do it properly you need a multimeter.

But if I had wired it up (I didn't) then brown to COM with that link wire going to the other COM (that should be your live feed in). black wire on one of the L1 terminals and grey wire on the other L1.

EDIT. you need to do some work insulating the black wire with the tape on it. There's a bare wire in there, that i can see. If that touches the metal box, then BANG!

Thank you

 

[Norwichcitizen]

Thank you very much indeed. I've tried exactly what you suggested and it works perfectly now - light in both rooms at last and dimmer works too. I have placed tape around the black lead where it entered the terminal so no bare wire sticking out now.

I've certainly learned my lesson though and will definitely take a photo next time before disconnecting anything!

Once again, many thanks.