Another lighting question

[MarkB]

I've been checking over the 77 Sport and got to the rear brake/tail light. Ignition on, tread on the brake pedal and it lights up. Turn ignition key another click to turn the lights on, and there's no tail light. And no brake light either. The headlight is fine. I've tried it with two bulbs, one of them new.

So, turning the lights on makes the brake light stop working, and the tail light doesn't work. Is there a simple answer to this or will I have to spend hours wiggling wires?

Thanks for any suggestions. Mark.

[dvhttn]

Hmmm. On my Sport the ignition key has 3 settings. The middle is 'off'. One click forward(**) from 'off' is 'side lights on'. One click BACK(**) from 'off' is 'ignition on'. The headlights on/off/dip/main is all controlled from the handle bar switch. Though I beleive there are two forms of switch so this may not apply to both.

HTH

** - I may have the 'back' and 'forward' the wrong way around but the principle holds, with 'off' being the middle setting.

Oh, I did find with mine that the electrics were doing weird and wonderful things when the key was turned. Took the ignition switch apart and cleaned it and all is now fine with the world .....

[MarkB]

Thanks Dave. I've got an earlier system. 9 o'clock (key horizontal) is ignition off; 10.30 - 1st click - is ignition on (electrotap goes clunk and red dash light comes on) and midnight - 2nd click - is lights on, which can either be pilot light, dip or main beam, depending on what I've remembered of the CEV snuffbox switches.

I had just washed the bike; maybe some water has got in somewhere...

[Ralph]

Could be a bad earth to the tail light.

[brianh0_4]

Yes, it's the earth, had the same thing last weekend!! The earth goes through the lamp body then the bolts that hold on the no plate. So either tap it!! or clean up the bolts.

[MarkB]

Guess what? You're both right! I've got an earth wire that runs to the frame/mudguard bracket bolt. Emery paper and a model-maker's file did the trick. I'm kicking myself because I know that 80% of electrical problems on Morinis are down to bad earths, and the other 20% are down to carburation. My mind over-complicated things because the brake light worked when the front and rear lights weren't switched on.

Thanks all, Mark.