Until the light switch, there is no "light supply wire". Merely the main permanent 12v to the ignition switch etc.

Ah! Does it spur off from this ignition wire, then? It would have to be before the ignition 'switch' since the lights work without the ign being turned on (an even bigger reason to have it fused...)

Thanks.

I've never had a loom apart and investigated properly, but that's certainly my assumption. Same with the other "permie-live" bits - hazards and sometimes indicators & brake lights.

I can't help feeling you're talking yourself into a complete rewire.

Complete rewire?! Jeepers, no...

I'm just going to add that fuse, that's all...

Hopefully.

It sounds horrible, but I want to drive over there and do it myself

Electrics isn't the easiest stuff to explain from distance anyway, but to try and advise on modifications is just frustrating, it's like asking someone the best way to build a bypass round modern day Moscow* using a '76 map without any of us ever visited there themselves!!

Download a good diagram, study it and judge for yourself. Fuses need to be in each circuit (sidelights are fused after the switch anyway) if you want to protect individual circuits or before the switch to protect all of them.

*I bet someone's been there!!

Hi Bertie.

Kind 'offer' - tho' I suspect born largely from frustration rather than Samaritan tenancies

Not to worry - honestly. I have clearly come across as a bit of a klutz, but I'm actually pretty au-fait with electrickery - having taught electronics to 'A' level...

I shall either trace the source of the main headlamp feed wire to the light switch, or else do as the sides do, and fit in-line fuses (sep main and dip) after the switch.

Peasy....


(Now, I'm sure that didn't smoke before...)

Here ya go D.A. it's your lucky day! I spent this afternoon wiring in the fuses for wipers and headlamps, that I mentioned earlier.

Firstly the light switch supply, as that's the one you're dying to know about!
Conveniently, the wire you want to intercept is not that far from the fusebox. Get your head under the bonnet and make yourself familiar with that big chunk of wiring loom that runs across the top of the bulkhead between the fusebox and the hole behind the dashboard, Now remove the wrapping from a section of if, quite near the middle, you'll find quite a few 'junctions' protected by their own individual piece of insulation tape. You're looking for a junction between 4 fat yellow wires, when you find it you'll notice that while all 4 wires are fat, 2 are slightly fatter than the other 2.

You should have 1 fat wire, and 1 'thin' wire, heading in each direction. the fat wire coming from the direction of the fusebox is the permanent live feed, I suspect it joins into the wire which runs between the starter and alternator. The thinner wire on the same side goes to the fusebox, and is the supply for the hazards, brake lights and interior light.
The fat wire that heads for the back of the dashboard is the supply for the ignition switch, and the thinner wire that goes with it is the supply to the light switch. I'm sure I don't need to tell you what to do with it but for every one else, cut the light feed off this junction. Attach a new wire of the same size to the junction, solder is best if you can, run this wire to the fusebox, through a fuse and back up to join with the light switch supply wire.

Other things I'm sure I don't need to tell you but will mention anyway. Disconnect the battery, the wires involved are permanently live otherwise. Remove the righthand front wing, sitting on the front wheel is a far nicer way to work than having to lean over the wing.

I did take some poor quality pictures to help explain this, but can't get them onto this computer. Also if anyone wants an explanation of the wiper fuse setup, say so.

HTH.

Hi Joolz.

Just seen you reply - been away for a couple of weeks. Haven't taken that harness apart yet, but what you say sounds very informative

Many thanks.