Problems connecting a 2 gang dimmer

Hello

I am trying to fit a 2 gang dimmer switch. It is replacing a normal 2 gang switch.

I have managed to get this working to a fashion. Both lights working from the dimmer. However whilst one of the lights works fine and can switch on and off and dim, the other only works (swithches on and dims) when the other light is on.

I thought i had wired this up in the same way as the switch i am replacing, but it appears not.

Also thought it worth mentioning, that the wires that i am working with are 1 Red, 1 Black from one cable, and 1 Red from another (the black is a there but is a little stump hiding at the back of the back box, and wasn't used on the old connection). With both earths connected to the metal back box.

Anyone able to tell me where i am going wrong??? Any help would be gratefully appreciated.

On your old switch was there a link between the two C terminals?

My guess would be
One of the reds to c, link to the other c

black to one of the L1s

the other red to the other L1

If that doesnt work, swop round the two reds.

If you're still stuck you'll need a test indicator or multimeter to work it out.

Thanks for your help that has done the trick.

Just in time for the missus coming home, at least she won't go mad at me for making a mess. She might even say thank you

Thanks again.