Citroen C5 x7, trailer Relay Unit (BSC) pinout

[Falka]

Hello!

Im looking for a pinout diagram for the Trailer Relay Unit (BSC B03 00) 9665778480.

I cant find anything in SEDRE regarding of the bsc unit and its wiring.
I'm mainly intrested in the trailer socket <-> BSC 16pin connection, also theres an extra pin for the trailer "status" (BSC -> BSI) thats not wired up in most x7.

Any help would be appreciated.

[GiveMeABreak]

Here you go, this is what I have:

[Falka]

Thank you very much.

[Falka]

The C200 ( trailer socket) pin layout shape doesn't match iso 13 pin plug pinout. Is there a different diagram for the eu iso socket or this is the only one?

[GiveMeABreak]

They do on all official Citroen 13 pin sockets - they match exactly.

Example from a Citroen 13 pin towing socket:

You'll have to click the image to zoom it up.

As you can see these relate to both the wiring diagram (C200) in my previous post above and the designations on a Citroen 13 Pin Towing Plug Socket.

Pin	Wiring Code	Description
1	28A9	Trailer rear left direction indicator control
2	20A0	Trailer fog lamps control
3	MC60P	Earth mc60
4	29A0	Trailer rear right direction indicator control
5	26A4	Trailer rear right side light supply
6	21A1	Trailer brake lights control
7	26A3	Trailer rear left side light supply
8	22A3	Trailer reversing lights control
9	BR03	Trailer fuse box fuse 3 output battery positive
13	MC60S	Earth mc60S

[Falka]

I understand now. Thank you!

[Falka]

Can i ask you what is 8801 on the diagram? The brake light wire goes into it.

[GiveMeABreak]

8801 is the Trailer Double Relay.

So I would suggest that this may be one of the relays in the BSR trailer fuse board fitted with the Citroen electrics wiring kit for towing.

[Falka]

8801 is the Trailer Double Relay.

So I would suggest that this may be one of the relays in the BSR trailer fuse board fitted with the Citroen electrics wiring kit for towing.

The diagram wiring is wrong

Today i actually checked on 3 x7 with factory fitted thüle towbar. The C200 -> 21A1 wire splits into 3 wire and ends in the BSR1 16V GR pin 6,7,15.
Everything works the way as it should.
8081 doesn't exist seperatly. Its on the motherboard, and theres no 10V NR as it shown on the diagram.

The trailer presence function also doesn't exist on these thüle sets. I saw other posts about this.
The wiring is mostly there but on the C200 (towbar connector) theres not a single microswitch for the presence detection. Or i was blind.
This function can be added by a simple toggle switch hidden in the trunk. 21A2 and 7508 are the wires you have to insert the switch into. In some factory installation, Z14 wire is missing, you have to make that too (10v NR pin4 BSR1 -> 16V NR pin3 BSI)

PFPR is just a fuse mount with a 2A fuse

I hope these informations will help others.

[GiveMeABreak]

Yes 8081 if the relay would be on the motherboard - just the same as the engine fuse box has relays and the BSI.

You have to remember that the kits are vehicle-specific and I can only comment on the electrics supplied by Citroen and not any aftermarket kits.

The official harness is specific to the DT20 engine, and is Part: 9428F8 and this includes the BSR.

This harness is particularly suitable for providing the lighting supply to trailers or cycle-carriers on tow bars.
This harness has been developed to incorporate all of the vehicle special features.
It also provides an electrical supply to the fog lights and reversing lights.
Comes with a 13-way socket to correspond to the trailer socket.
It incorporates all the features needed for good compatibility with this vehicle and is SAFE, RELIABLE and EASY to fit.
The functionality of the harness will be obtained by configuration of the BSI (fitting by the network is imperative).

Here are the fitting diagrams for reference: