C5 Left and Right Brake Lights not working

[John7140]

Hello,

I started looking into my brake lights not working and I seem to be hitting a wall. Working on a 2005 Citroen C5 Estate.
My Problem: Both the Left and Right Brake lights are not working. However the high mounted centre light works fine. Starting at the lights, I pulled the bulbs and changed them with the tested and working reverse bulbs. I then checked for power in the socket. No power is getting to the socket. I moved to the Fuse Box. Both the fuses are in good shape. Checked for power at the fuse and both lights are getting power into the fuse box. I also checked the brake switch just in case, even replaced it. Switch works fine, and checked for power. Power gets to the switch. I tried doing the BSI reset in hopes it was related, but no luck.
From what I can tell from the research I have done, the brakes lights are wired into the BSI. Is there a diagram that shows which harness and pin is which for the BSI? Is there a wiring diagram somewhere so I can see where to go next? Or does anyone have any further suggestions?
From what i can tell there must be a problem before the wire splits to go to each side of the car, so I assume before the Fuse Box, but i have no clue where that wire is.
Thanks ahead for any information

[xantia_v6]

It is probably worth trying a BSI Reset / Battery Disconnect / Reconnect Procedure before anything else, I think that there has been a case reported here where that fixed a non-functioning brake iight.

[GiveMeABreak]

... I tried doing the BSI reset in hopes it was related, but no luck.

[John7140]

It is probably worth trying a Battery Disconnect / Reconnect Procedure before anything else, I think that there has been a case reported here where that fixed a non-functioning brake iight.

Yeah, I tried that. Even tried a few times just to be sure.. No luck unfortunately.
Thanks for the input though.

[John7140]

So I have been trying to chase the wire, and pulled apart just about everything. Does anyone have a wiring diagram for the system? I am going searching for a Haynes tomorrow at the local auto shops, but figure it was worth to ask here.

[Stickyfinger]

Just checking......you did the BSI reset WITH the new bulbs in place ?

[myglaren]

One thing that seems to cause mayhem with C5s is inserting a dual-filament bulb the wrong way round.

[darbuck]

I had same problem with my estate recently turned out to be brake switch check connection before replacing as the cable in mine has a tendancy to get knocked out. Its located under glove box behind carpet switch cost 15 euro from flea bay with postage to Ireland so i,m sure you'll get it for a lot less in the uk . hope it helps.

[Peter.N.]

The problem I used to get with XM estates was the wires breaking where they go from the body to the tailgate.

Peter

[darbuck]

yeah i had that on a primera and rover estate aswell it seems to be something all marks suffer