lighting murders!

[hil112]

Help, I am a competant DIY person, but this simple task is now the bain of my life
Bedroom lights swapped over. easy enough? NO! i must have done the classic and lost a switch live as no bedrooms (3 number) worked.

After a while with a multimeter i found the switch live in the first bedroom.
This has been connected and i have the light working
Lights don't work in other 2 bedrooms (1of them i never touched)

I started to look for continuity in the 2nd bedroom where the light was removed.
I have 2 reds (together) and only 2 blacks (separate) (plus earth) in this room. it is on a dimmer switch which i changed over for a normal one, in case that was faulty.
240V on reds in ceiling rose / switch and 150V at switch when switched on. I cant find continuity / switch live for love or money. i have had a couple of gueses and the light still wont work. It did however, start switching the first room wired earlier. so I put all back as original.
(2 reds in block and 2 separate blacks.)

Could the first light i wired be still faulty although working?

2 blacks in floating block connected to blue lamp holder
1 black (switch) connected to brown lamp holder
3 reds all together in ceiling rose
Earth - No issues

is the reds together causing me the problem? Im sure one was by itself previously

what is going on????? 2 minutes marking up at the beginning would have saved me all this aggro!

 

[conny]

In the second bedroom, with the power isolated at the CU, split the 2 reds.
Select 1 red and find its matching black, with your multimeterset to ohms, by operating the switch. these are your switch wires. Mark the black one with a brown sleeve. Reconnect the 2 reds in a suitable block. The single black and the sleeved black should now be connected to your fitting terminals where the lamp leads are. This seems to me to be the last light in the circuit if it only has these 4 wires, (I am presuming singles rather than grey T&E).
Look in the Wiki at lighting circuits as well.

 

[PrenticeBoyofDerry]

You say two reds together and two blacks separate.
Are we talking connected or in PVC sleeving?
You should find continuity before you start messing about with live voltage, so competency test you have unfortunately failed .
Also failed the idiot proof test of taking notes of cable positions before you disconnect them.
Can you post photos of what you have?
You say first light works but rest don't.
What happens to the first light when the others are turned on?
If I were you I would testing for continuity at the switches, with power off.
Closing switches and testing between pairs.