Posted on

2CVGB News article – SPOG February 2017

To bring in the New Year Taffy sang “I’ve got a lovely bunch of Halogen bulbs, here they are all standing in a row.” Hope yours was a good one too. But now with all these new headlight bulbs to hand, onwards to fit them including the necessary relays.

You’ll remember from last month my various purchases of wiring products. Well, in between pulling Christmas Crackers, the bonnet was up on my F reg 2cv outside. Indeed for a while I became an auto-electrician … allegedly.

Firstly I mounted the twin relay unit on the bulkhead bracket where my Boyer Bransden electronic ignition box sits. On the back of each relay are four electrical spades with corresponding numbers embossed in the plastic housing. As my relay unit came with no fitting instructions, hmmmm, a little research needed I think.

In the design of electrical power systems the ANSI Standard Device Numbers identifies the features of a protective device such as a relay or circuit breaker. This system of standardisation apparently originated in 1928 with such numbers still in operation today. I have drawn a diagram of a single relay unit showing these numbers and what this means to us 2cvers when upgrading standard headlight bulbs to Halogen examples if following my modus operandi.

Firstly after mounting my double relay unit to the car I made up two brown earth wires which I fitted to the spades numbered 85. I then went to the front of the car and removed the plastic cover over the electrical connections underneath the left hand side of the light bar. To test my theory I put the dipped headlights on and pulled apart the green coded connectors. The light went out, although the right hand headlight stayed on. All good so far. Then switched the headlights to main beam and pulled apart the yellow connectors. The light went off again with t’other one still glowing brightly. Bravo, this is making sense.

Next, and this is most important, I REMOVED THE POSITIVE TERMINAL FROM THE BATTERY. Yes, electrics do frighten me. Now safe, I started to play. Taking the new green and yellow 8.75 amp thinner cables, I crimped on red male bullet terminals and pushed these into the sockets on the loom I had just disconnected matching colour for colour. These wires were then run backwards towards the bulkhead and, with suitable blue female spade terminals attached, pushed onto the relay unit’s spades coded 86.

You’ll see from the attached photographs that everywhere I kept the colours of wiring to match one another. All green wires to one relay socket, all yellow wires to the other. I told you I was a novice at this!

Now for the power source. I was recommended (thanks Ken) to pick this up from the blue terminal on the starter motor which is constantly live. I know because I checked it. Here using ring terminals attached to the thicker 17.5 amp wires, I also ran these two cables (one yellow, one green) back to the bulkhead. But before attaching to the double relay unit I fitted in-line fuses to both lines with a 10 amp fuse inside. With in-line fuses in position, these 17.5 amp cables went onto the relay spades numbered 30.

And finally the fourth dimension. Two (again one yellow, one green … I am a simple fellow) 17.5 amp thicker cables were attached to the relay unit on spades coded 87 and brought forward to the light bar. At the light bar I fitted piggy-back terminals to each cable so that 17.5 amp yellow wires and green wires could go to either headlight. On the left hand side I crimped on female red bullet terminals and pushed these (yes, you’ve got it, colour for colour) onto the round male pins from the wiring loom connections I had previously pulled apart at the beginning of all this.
On the right hand side underneath the light bar I now exposed the electrical connections found here from within the plastic cover. As before, green and yellow unions were disconnected. Red female bullets were crimped onto my new cables to attach these wires to the original male pins, green to green etc.  The female sockets from the loom are now redundant, so I blanked them off with small rubber bungs. Job done (let’s hope) after everything adequately insulated and suitably held away from the engine’s hot bits.

Finally I replaced the positive terminal on the battery and stood back. No smoke, no bang! Confident or what? Started the car, yes it ran perfectly. Now for the headlights. Dipped worked both sides as did main beam. You’ll notice that I hadn’t replaced the headlight bulbs yet. Because I was not totally sure of the science behind this (although I am now) I left the standard bulbs in situ. If I was going to destroy bulbs with my efforts, better it were the cheaper ones compared to Halogens.

With this new relay system in position I noticed the standard 40/45 watt bulbs looked brighter already. Just goes to show how much potential “drop off” in current is caused by the wiring/light switch in the original system. And when the Halogens went in … Wow!

The beauty of this method is that if LED P45t headlight bulbs ever appear (do you know something that I don’t?) then this whole feast of wiring spaghetti I’ve just added to my 2cv can be simply removed with everything returning to Citroen’s original design. What larks.

David Eden SPOGman