Can anyone help with a Ford Focus?

Hi all,

Wonder if anyone could help, I tried looking everywhere online put have now given up!!

I have added a tow bar to my mk1 ford focus but cant get the wiring sorted out? I'm trying to get the wiring sorted out as I've gone through the boot and tried to connect the wire to the blue box under the carpet on the left hand side of the boot but, haven't a clue what color goes where and what it does. I know the wiring type for 7way plug but the rest is got me. I did mange to wire it up to what I thought was ok and it worked fine until I turned the lights then the left hand indicator game on on stayed on? Doesn't flash. I'm lost and have now disounted it and can't remember what goes where? Oh yeah I haven't got a mutli meter neither.....any advice?

Thanks in advance!!