) This should be around 17 amp capacity - whilst you could probably get away with 8 amp rated cable, voltage drop along it will be greater and it's also physically less durable due to its size.Starting with the lamps themselves, run a wire from the terminal on the bulbholder to a good clean earth. Up in the engine bay is probably better than using the lamp fixing bracket as it's less likely to get corroded as quickly. Run another wire from the flying lead on the bulb in each lamp to the relay location.
If you are using a relay with a built in fuse (neater and easier), it's better to keep this close to the battery to minimise the length of unfused circuit. If you wish to put a relay with the original relays on the bulkhead, it's best to put a separate fuseholder close to the battery for the same reasons. Note that I haven't done this (do as I say, not as I do!), but I have run the unfused cable within the same trunking as the original loom so it well protected against chafing/damage. I've used a 20 amp fuse as I'm also running 100 watt spotlights from the same circuit, although don't have them both on together.
Connect up both wires from the lamps to terminal 87 on the relay. (There is a guide to relay operation here.) Connect terminal 30 to the positive terminal on the battery, via the fuse if not using a fused relay. For neatness I used one of the spare terminals on the two 3-way connectors coming from the positive terminal.
Connect either terminal 85 or 86 (it doesn't matter which) to earth (the relay securing screw is ideal) and the remaining terminal is the one which will be connected to the switch to make the lights come on. You can test the wiring up to now by touching a lead from this terminal to battery positive. The relay should click and the lights come on.
Run the switched wire into the cabin via a suitable grommet, and take it to the position you want the switch. If you are using a standard illuminated switch simply connect the switched terminal to this wire, the earth to the bodywork and the feed into the sidelight circuit.
With the original Citroen switch, the process is much the same except there are 5 terminals and they aren't handily marked for your convenience! It's easier if you have a short section of the loom with the connector to plug into the back of the switch, but if not you'll have to use standard female spade connectors.
1) feed from sidelights
2) output to relay
3) warning lamp
4) earth
5) switch illumination
Link 1 and 5 and connect to sidelights (the lights on buzzer is handy to tap into)
Link 2 and 3 together and connect to the relay trigger wire
Connect 4 to earth (I spliced into the earth for the mirror switch)
The internal bulb is powered via a resistor when the sidelights are on, but when the switch is in the ON position it gets full battery voltage and illuminates brightly.
Finally, make sure all wires are secured, and job done! Have a beer. Facebook photo optional...
), into the firewall and out to the battery from the inner wing cause the relays to perform less than ideally? 