Hello.

Thanks to posts on here I now know which wires supply the headlamp switch and feed off to the various bulbs - thanks! I've also read confirmation that the main headlamp bulbs aren't fused... Jeepers. AND they are supplied direct - not even via the ignition switch.

As one of my two 2CVs (there's a story here - I'll post it soon. Just to whet your appetite, I found one of them locally and it's only 'one year' old...) is a bit tatty 'though solid, and will surely begin to develop some electrical quirks somewhere along the line, I'd like to ensure that one of these lecky foibles does not include a complete wiring loom meltdown by adding the 'missing' fuse.

My intention is to completely replace the existing fusebox with an 8-way unit. One of the extra fuses will be used to supply the headlamps and t'other will provide power for ICE (I have an idea here too, one of which might be on interest - I'll post that too.)

Ok, I reckon my options are to (preferable) use two fuses for the lamps - one for the main and one for dip. Advantage: lower rated fuses so 'safer'. Also if one blows, hopefully you should still have some headlights. Disadvantages: the feed to the light switch won't be protected, and more cutting into existing wires.

Or, use a single fuse in the supply to the lightswitch. Advantage: most of the wiring should be protected (eg: if the feed wire shorts where it passes through the bulkhead), easier installation. Disadvantage: a single fuse has to handle all the lighting. One 'pop' and you are in darkness...

What are peoples' thoughts?

Thanks.

That's exactly what I've done. For now I've just fitted an 8 way box with the outputs from the light switch fused but I intend to install relays as well which should lighten the load on the switch.

Hi Bertie. That was quick! Thanks for the reply.

So, you fitted the fuses after the light switch, on the supply routes to the lamps?

Can you tell me where you cut in to the cables (save me running out in the rain to have a look...)?!

Yes, I hate the thought of the light switch having to carry that load, but I doubt I'll bother going the relay route - very good idea, tho'.

Thanks.

D.A.,
on any cars which have it fitted, it's best to bypass the dim-dip setup as soon as possible, before the switch is overloaded.
The clue is the pair of relays fastened to the bulkhead next to the battery, or hanging off the main loom in that vicinity, as well as the resistor on the chassis front cross member.

Don't forget that some older cars may have been fitted with a later wiring loom, if their original loom had been damaged.

Ken.

Unfortunately I can't help you there as I completely re-wired the Bedouin from scratch.

Hi Ken.

Yes, one of them is a 1989 model, so dim-dip. I've many posts - mostly by CViking, I think! - about the perils of this setup, and how to by-pass it. That's on the agenda.

No problem, Bertie, it shouldn't be too tricky to sort it out - it's a gloriously simple wiring system!

Thanks all.

Hi D.A.
I replaced my fusebox with an aftermarket 8 spade type recently, It's a late model car so it had 5 fuses as standard, the other three spaces have been allocated to, accessories, wipers, and headlamps. I'll just have the one fuse protecting the feed to the headlamp switch, if Citroen think having no fuse is good enough then one fuse must be more than adequate, and also because there's only one space left in the box.
The accessories fuse is fed from the 4-position ignition switch and the wiper fuse is on a spur from the standard feed, hopefully you know what I mean by that. The thinking behind having a separate wiper fuse was that it's not unknown for wiper linkages to jam when they get worn, mine is probably more at risk than most as I've modified it. If the linkage jams and blows the fuse with the standard set up you also lose (from memory) the indicators, fuel gauge, oil pressure light, and charging circuit (a bad thing!)

Having said this I've not sorted the headlamp or wiper fuses yet but will try and put some pics in the 'My A-series' section when I do.

Thanks, Joolz.

"...if Citroen think having no fuse is good enough then one fuse must be more than adequate..."

Good point - it'll be a significant improvement on sod all!

I like your thinking about separating off the wiper too - the more spread out the protection, the fewer things you'll lose when one fuse goes 'pop'.

As it almost certainly will...

Cheers.

DA - this is the important bit. RELAY them.

Take the existing light switch feed, and use that to switch the relay. The relay then switches a feed straight from the battery (fused as near the battery as possible).

The amount of power a feed normally carries doesn't make any difference to whether it should be fused or not - any short is capable of carrying as much power as the battery can supply. Until the wire melts, anyway. Or a fuse blows.

If you want to fuse everything, then you're looking at a complete rewire - you'd go mad trying to modify the existing loom, I'd think.

Hi tm2cvs.

Yeah, I understand the use of relays to lighten the load on switches, but don't think I'll go that far - the switch has lasted 24 years so far and this model doesn't have dim-dip. I like to keep things simple! Also, the now 'lighter-load' relay switching wires going to the light switch will also need fusing or else they could still pose a problem.

I think I'll settle for a fuse (possibly in-line type) in the main light switch feed. A pair of headlamps with 4 side lights is around 100-120W? So a 15A fuse should have plenty room to cope but should also pop fairly quickly with any 'short'. (Or perhaps I'll fit them on the headlamp 'return' from the switch so that the headlamps are fused separately to the 'sides'...)

I'd like to fit this fuse as early as possible in the circuit - I'm guessing the main light supply wire is amongst the bundle running along the engine bulkhead past (but not visiting!) the fuse box?

Fitting relays is a good idea, but if this supply wire isn't in itself fused, then it could still 'short' on its way to the light switch and wouldn't be protected (although the most likely areas for shorts will be on the supplies to the actual lamps.)

There's a photo of the switch wiring on here somewhere - I found it before - does anyone know where this (was it yellow?) main light switch supply wire supply routes from?

Cheers.