Wiring A 2010 C3 Picasso Towbar

[c3pete]

Hi

Having recently bought a 2010 C3 Picasso (Exclusive) I have decided to fit a towbar for my small trailer. I have fitted towbars on all my previous cars, but this is the first Citroen.

I am hoping that someone can advise me of the procedure for wiring in the relay unit please?

Cheers

[paul.h]

Welcome to the forum.

 

Citroens have canbus wiring so options are to fit a dedicated wiring kit for your car (there may be a trailer wiring connector hidden somewhere in the boot area or at the side of the boot behind a panel - fuses are listed in the car handbook and these may be permanent live supplies) or to fit a lower cost relay kit taking its 12 volt supply from the battery with a 15 amp fuse at the battery end - or using the permanent live supply in the trailer socket from the fuse box. With the relay kit you will need to identify the correct light wires by removing the rear lamps and tracing them back to a suitable point to splice in (scotchlocs) - Citroen tend to use a number sysem rather than colours which makes it a bit harder to follow them.

 

Remember to tell your insurance company you have a towbar, it will not cost anything but stops them avoiding paying out on a claim since you have a modification.

 

(I have moved the post in to a subsection since ones outside do not show after a few days and are not easy to find)

[c3pete]

Thank you very much for the information and must admit I had not thought about informing the insurance Co, who as you suggest would use that as a "tool" in the event of a claim. I have a bit of a problem with the removal of the access panels as I do not want to damage them and also I need to identify the constant 12v supply at the glove compartment as i will be fitting a bypass relay  (TT17-2). Am I right in my assumption that the wires for all the rear lights run down the left hand side and hence there is no need to disturb the righthand access panels in the boot.

Really grateful for all your help.

Regards Pete

PS Are there any pictures of the removal of panels and access points for wires online? :unsure:  

[paul.h]

I copied this from the Citroen Picasso forum (sister site to this one) which may help a little bit.

 

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This is what I (Lapin 127) posted on the Forum in April last year:-

 

Tow bar electrics now fitted! Behind the Boot Light, there is a handy bit of flat plastic trim where the relay can be mounted and a 6mm Stud for an Earth. I have taken a heavy cable from the Fuse Box in the Glove Box, as I have also fitted an accessory 3-way Socket (cig.lighter socket) in the boot for Mini Fridge etc. On the Fuse Box board, there is a connector block with heavy red and white cables, I have taken a fused feed from the live Red wire, which does not appear to be in the 'Economy Mode' circuit. It was quite easy to take the new lead to the boot, under the internal Sill Trims. Feeds from the N/S Tail light, Indicator and brake light are needed, plus another feed from the O/S Indicator (over the top, under the edge of the Headlining and down the n/s c-pillar). You do not need feeds from the O/S Tail light or O/s brake light, as the Relay just needs a single feed for each. Everything fine after inserting the fuse!

Regarding using the feed off the Boot light, haven't tried it but suspect it may take too much current, especially if Tail lights, Brake lights and an Indicator all work together. PLEASE NOTE - if you are not TOTALLY confident in splicing into existing circuits and working with car trim removal, DO NOT try this job - you will be safer to take the car to a competent, insured Auto electrician; 'cooking' an ECU or Wiring loom could lead to a very expensive bill!

 

 

My installation has worked perfectly - note the last line - I have had a lot of experience with car wiring, the first rule is ALWAYS put a fuse in the new live feed you have installed - even then, if the circuit you have spliced into has a low power consumption, the 'computer' may see it as a fault!

 

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However, you do not need to follow this. When I did our C5 estate for towing a caravan, I used the fusebox 30 amp trailer live feed wire (thick beige wire) to the existing wiring connector, which I found behind a panel at the left side of the boot, as a supply for one of the bypass relays and therefore able to fit its fuse in the fusebox. The wiring loom (as in other Citroens we have had) ran from the glovebox fuse box down the left sill and to the left side of the boot and the left lights, continuing over the top to the right side lights. I removed the rear lights to identify the correct wires for each bulb (colours and identification numbers - most of them are white) and then found them in the loom at the left of the boot. The relays (12N and 12S) were mounted at the left side and spliced into the relevant wires in the loom using scotchloks.

 

I suggest that you do something similar, check at the fusebox that the trailer fuse points are live first and then find the trailer socket in the boot, most likely at the left side behind the panel. Use the permanent live wire from this for your relay live feed. Then find the correct wires for the lights - light removal will be in the handbook for bulb changing.

 

This is based on the Citroen manual: To remove the boot side trim panels - move the seats fully forward, partially detach the boot aperture seal (not sure if this is needed), remove the rear parcel tray, remove the torch, remove the bolts from what may be the torch location, unclip the panel from the top and sides - it looks as if the top clips to the upper panel and the sides use plastic clips a bit like press studs, (once you have undone one clip you will know what to do but sometimes these things break) so try doing the sides before the top, undo the torch electrical connector and remove the panel from the car.

[c3pete]

Hi Paul

Sorry to trouble you again but I am having problems locating the R/H indicator wire in the loom. The colour on the light cluster is green but it obviously changes colour between there and the place where it joins the loom in the L/H side of boot. I am assuming that the wire is the same thickness and having checked wires of that calibre I still cannot find the one for the R/H indicator.

I have found the wires for the Brake lights,L/H indicator, L & R/H rear lights However I still need a pick up wire for the fog and R/H indicator lights which are driving me nuts! I have fitted towbars to Fords, Toyotas, Nissans, etc. but have never encountered such problems as this vehicle :-(.

I have tried looking for the "wiring number" on the R/H indicator unit but it is not at all clear and the fog light colour is pink but that must change colour somewhere along the line.

 Maybe the R/H indicator wire runs down the R/H side of the car?

Thanks again for your help

Cheers Pete

[paul.h]

You will probably find the wires run from the lights across the roof to the left side. If so to access/see them the headlining will need to be lowered slightly at the door opening - but if doing this it may be easier to just run a couple of wires across the roof tucked under the door seal (or even across the rear of the boot and behind any plastic trim) to the left side and then you know what you are doing and it is likely to be quicker for you.

 

In post 4, Lapin 127 says the feed from the O/S indicator is taken over the top under the edge of the headlining and down the C-pillar. This reads as if a new wire may have been run. It does not mention the fog light.

[c3pete]

Hi Paul

Thanks again for your reply and advice. If the wires as suspected run under the head lining, then they have to come out into the loom on the nearside? I have tested these wires( which i have not already connected into) the colours of which are  grey x 2,yellow and orange (twisted together),white x 2, green/yellow x 2, purple, pink, orange, red. and cannot find the R/H indicator supply.

Dropping the head lining is not an easy option as the two securing "plugs" do not want to budge and I do not want to wreck the lining. So as you say I am left with the option of running a wire down behind the plastic trim at the bottom of the boot. Problem here is how to feed the wire? Do I feed it through the rubber grommet where the R/H light cluster wires enter the body and hope that the wire drops down behind the plastic trim in the R/H corner of the boot? 

I am not really bothered about the fog light, it is just this R/H indicator which is the pain.

Shame that there is not a wiring diagram out !

Cheers

Pete 

[Johndouglas]

When I wired my C5 for towing I connected to every wire I needed at the back of the two bulb clusters. From each bulb holder, the new wires connected to the relays which fitted into one of the two 'cupboards' in the load area.

[paul.h]

Without seeing your car it is a bit difficult to suggest the best options, especially since you are trying not to remove and possibly damage the trim, which is understandable. It could be if you pull off the hatchdoor seal at the top of the opening, you will be able to push/run the wires just under the lining (as done by Lapin) without lowering the lining. To connect to the wiring at the back of the light and not inside the car body may work but it could be affected by damp unless you can seal it well. Before you connect the wire, try feeding it through to see where it comes out.

 

When I did the C5 estate I removed both side trims, removed the boot rear trim, removed the rear seat belts, removed the left sill trim, the rear lights, the rear top side trims to get at the wiring. I only broke a few of the plastic clips that hold it together and these were not expensive from the dealer.

 

If not already done, if you register on the service.citroen site as another professional, member of the Citroen Owners Club. As a free service you can see the parts diagrams which show the wiring looms. You can also pay for extras on a timed basis and this may include wiring diagrams, but I am not sure since I have not used this.

[c3pete]

Hi Paul

Have managed to connect the R/H indicator now thanks. The wires run down the R/H side of the car and can be accessed just inside the R/H rear door, just spliced into the wire and ran it round to the relay unit. Just got to splice into the power supply now and that should be it :-)

Cheers

Pete

I will try and find the service Citroen site and register.

Edited November 30, 2013 by c3pete

[paul.h]

A quick look at the parts diagrams shows the fog light is at the right side of the rear bumper and the wiring runs inside the bumper to the left side.

[c3pete]

Thanks Paul

[paul.h]

If you are ok with French or using a dictionary, the French RTA manual for the C3 Picasso may be useful from such as Amazon. It is like a Haynes manual but in French and includes wiring diagrams. http://www.amazon.co.uk/B745-Picasso-1-4vti-1-6hdi-Depuis/dp/272687455X/ref=sr_1_fkmr1_1?ie=UTF8&qid=1385844100&sr=8-1-fkmr1&keywords=RTA+c3+picasso+manual .You can also get Citroen manuals on dvd from such as ebay at low cost.