Lights!!!

[Geocamper]

Out for a spin last night and the headlight and rear light stopped working. Also the main beam wouldn't work.Switched to the side lights and the front and rear were both working fine. The brake light is working as normal. Before I start taking things apart that are irrelevant to this problem is there any chance of a few pointers.
Edit!!!
Just checked the regulator and the yellow wire had come off. Happy days I thought?!!!
What I see now is the connection on the yellow wire is black. Looks like a burn out. Any ideas?

[Raveydavey]

Is the feed from the stator ok? Have the bulbs actually blown? Regulator should be ensuring a constant voltage, so you should in theory get a steady 12v from it for running the lights. Check it with a multimeter. If it's all over the place the regulator is not doing its job.

[Geocamper]

The feed looks fine. Plugged the yellow wire back into the regulator and the lights are all working correctly again. I just can't understand why the connector came off as it was connected tightly and also what seems to be black around the connector as if it has burnt out. As you say I can only find out if it's the regulator by using a multimeter. Cheers