DIY Doctor UK DIY Forums

I thought the two bulbs had gone in my son's bedroom so swapped one bulb and tried again. After fiddling with the dimmer for a while the bulb I hadn't swapped flickered on then went out. I figured it must be the dimmer switch itself.

I don't particularly like the dimmers in my house and my teenage son does smack the poor things every now and then so I figured it would be better installing a normal switch.

The existing wiring on the dimmer was:

• C one blue wire and one black
• L1 a red wire and a yellow wire
• L2 a single red wire

I wired it up the same with the new switch but neither light comes on. The fuse isn't blown. I do have a multi-meter if required.

Any ideas?

I will guess as there is no specific rule as to what colour goes where.

Swap L2 with C

And always take pictures.

I will also guess the light can be turned on / off from another location?

There's only one switch in the room and two little halogen bulbs in the ceiling. Am I still OK to swap the wires over?

Thanks for replying by the way!

As I said previously there is no specific rule as to what colour does what or where it should go, but, the fact you have a twin and earth and a 3 core and earth implies there is or was another switch, pull cord perhaps?

Yes, still swap them over (The red must stay as it is now, on its own)

OK swapped L2 and C over but still no lights. On the plus side I haven't blown all the fuses yet or electrocuted myself!

I was curious about the other switch you mentioned and did eventually find a pull cord hidden at the back of a fitted wardrobe.

Any idea what should I try next?

The way a 2 way switch is wired (in a nut shell) is one single wire at the top (C)
and two wires in each of the bottom terminals.

So if you had a red single it should be on its own at the top in C (common)
when you swapped L2 and C around, make sure that both wires in L2 are actually making a connection, no harm in checking L1 either.

Since it was working before you changed it, and there are no electronics involved, it has to be a airing configuration error, but you are sure you have them right, so it must be a connection (or not) problem.

With a 3 core & earth 2 way switch wiring the yellow should go to the C (common) on both switches with red and blue/black (from the same 3 core cable as yellow) to L1 & L2 and the other 2 wires (from the twin cable) into L1 & L2. This twin cable goes to the light fitting and will not show at the pull switch.

The 3 core cable is really just linking the two switches.

Skid Sprocket wrote:With a 3 core & earth 2 way switch wiring the yellow should go to the C (common) on both switches with red and blue/black (from the same 3 core cable as yellow) to L1 & L2 and the other 2 wires (from the twin cable) into L1 & L2.

Sorry to say but as i have said before, there is no specific rule as to what colour goes where, so to say Yellow must go to the common is not a definitive response, since it depends on what colour who ever wired chose to use.

And since the op did say he had a black and a blue, and a red and yellow already as pairs........

Mike bike kite. The pull cord you found, any possibility you could gently take its cover off (it will unscrew) and see what colour wire goes to what terminal?

I'll have my next attempt tomorrow morning when it's light. I'll have a go at seeing what the connections are to the ceiling switch but it's at the back of a top cupboard and I'm not sure I'll fit.

Would it help clear up things if I used the multimeter on the various wires?

I've attached a picture of the wiring to the other light switch. It's quite difficult to get too so this is probably the best image I can get. Hope it helps.

Sorry, I am busy today, but what happens if you "switch on" the pullcord?

Looking at that picture & assuming it is joined to your switch, but it doesn't sound right to what you was saying on your connections. IE:
"The existing wiring on the dimmer was:
C one blue wire and one black
L1 a red wire and a yellow wire
L2 a single red wire"

The reason i say this is the pull switch has the red as common "C" & wouldn't work with you connections as the red would have to be in C at your switch

if so & at the switch, take the red from the 3 core & put it in terminal C. Now you have 2 cables left from each cable at the switch. Put the wellow from the 3 core & the red from the twin in L1. Now put the remaining 2 cables in L2 & test.
If its still not working there might be a fault with the pull switch. To test this, take the red & blue out the pull switch & put them together in a conector, test again.

Collectors, I asked mike_bike_kite a question to which he has not replied, I am willing to bet that he will not reply to you either...........considering I asked over 6 months ago.

[quote="Mr White"]Collectors, I asked mike_bike_kite a question to which he has not replied, I am willing to bet that he will not reply to you either...........considering I asked [b]over 6 months ago. [/b][/quote]

Ah! your right, i just clicked on new posts & for some reason this one came up. Didn't check the date. lol. I take it that the problem was solved or he is no longer with us?. :)