Peugeot 407 Hdi 2.0 2009 Brake Lights not working ABS/ESR er

[barrymurphy]

I assume as the side lights are working it cannot be an earth issue.

[barrymurphy]

I got the car read with a professional code reader and it came up with a BSI fault.
So that makes sense.

Recommended actions? Thanks

[barrymurphy]

I have done a BSI reset and no joy.
I believe I need a BSI repair or clone my own to another unit.
But before I do that I want to place 12 volts to the relevant pin for the brake lights that is part of the plug that inserts to the BSI. This to eliminate a wiring issue.
If the brakes light up then I know its the BSI for defo.

My question is what is the simplest method of getting twelve volts to that pin. I could run a wire from the battery positive? Not sure about methodology and earths etc

[dfabrici]

Well, if you look at the schematics you already have direct battery supply at the BSI, on pins 1 and 2 of the 2-way grey connector (think it's one with thick wires, since the seem to carry the whole current used by the bsi). You can run a jumper wire from there to pins 14 and 15 (one at a time) of the 40-way white connector, the rear lights should come on. No need to provide earth, since it's permanent and common to all the bulbs on the tail lights themselves.
The lights are driven by the processor itself according to the diagram. There's probably a mosfet or a transistor driven by a low current output of the processor. If you have some knowledge, you may try and find what IC actually drives the tail lights. Beware that many BSIs have a sandwich construction, with 2 circuit boards stacked. Many times the connections are not soldered but just press-fit, and with vibrations and time may get loose. If you have a multimeter, you may also measure the output on the pins above (14/15 white plug) to see if anything is outputted at all.
About ABS, you must obtain the error codes to get a grasp on the primary cause.

Davide

[barrymurphy]

Thanks dfabrici.

For clarity I run a wire from pin 1 OR pin 2 to 14, check lights and then to 15, check lights. Correct?

And for measuring the output with my multimeter, black lead to earth/ground/metal and red lead into pin 14 and then the same for pin 15?.

This BSI is a single board. Are the relays for a 407 built into this board? or where are they located?

Thanks

Barry

[dfabrici]

To measure the output the procedure is correct, black lead to gnd (any good unpainted metal bodywork will do), red lead pins 14/15, dial on VCC, press the brake pedal and read. You may have to buy thin multimeter tips to be able to make contact on the plug, as the metal might be quite far into the plastic. It may be needed to dismantle the back of the plug to gain access to the pins. Beware, when making the bridge, that the pins 1/2 and 14/15 are NOT on the same plug! Pins 1/2 are on a 2 wires grey plug, the others are pins 14/15 of a 40 wire white plug! Check numbering (should be on the socket) to find which ones are pins 14/15.
Relays are in the BSI and the BSM, depending on the load they're connected to. 99% though brake lights don't have a relay to turn on, but an IC that acts as switch.

[barrymurphy]

Thanks, I am aware they are not on the same plug but I want to clarify that I jump from either 1 or 2? and do not need to jump from both at same time.

[dfabrici]

Ok, I just wanted to clarify to avoid any misunderstandings Pins 1 and 2 are actually shorted together before the maxifuses in the bsm in the engine bay, so it doesn't matter which one you choose. I'd put a fuse along the wire though, low amps (2 or 3 should do, since the bulbs are 21W so a bit less than 2 amps), to avoid any nasty surprise. It should be safe to do even with the 40 way plug inserted in the socket, in my opinion, but if you prefer to be safer you can unplug it and run the wire only in the plug in the pin holes.

[dfabrici]

Actually, just thought about that, to see if there's no break in the wires or bad contacts, you can also probe with a multimeter in ohms between pins 14/15 and gnd (plug removed, not fitted in the bsi), it should show something in the very low ohms range (filament is almost a short at room temperatures), unless you mounted LED bulbs.

[barrymurphy]

well, some interesting and confusing results. I removed pins 14 and 15 from the 40 pin white block, and one at
a time I placed the pins into the 2 pin grey block from the battery from which there was 12.77 volts. When i did this and measured the voltage at the relevant wire in the 6 pin connecting block at the tail light I got 12.77 volts!! same for both sides. The brake switch does not come into it as it sits before power hits the block and so is bypassed doing this. I placed the black lead onto the earth that sits just below the light cluster and one to the relevant wire in the six pin block and it read 12.77 volts. Plugged the 6 pin block back into the light cluster and no brake lights.

What can this be? Surely if 12 volts are at the connecting block then the lights should go on. And the tail lights do work, so eliminating the earth as the earth is shared by the whole cluster?. And there is a separate earth for each side.

Both sides are behaving the same.

[barrymurphy]

I have tested the earth in the 6 pin block at tail lights. Black lead pin 4, and red lead pin 1.

12.77 volts. Both sides.

I ran a jumper wire from the earth and a jumper wire from pin one to the bulbs and the bulbs lit up on both filaments. Yet when you plug the 6 pin plug in to the taillight no bulbs light up.

I have power running to both plugs, confirmed with jumper wires that the power will light up the bulbs, so what is wrong with the tail lights?

I assume they should light if there is power at that 6 pin plug and there's nothing else that should stop that?

I checked for voltage at the bulb receptacle with the 6 pin plug plugged in and there is none.

[barrymurphy]

And even stranger it is the same for both sides

[dfabrici]

Hi
So if I got it right, with the bulbs in their sockets, taillights connected (as if regularly mounted on the car), jumper from pin 1/2 to 14/15 in the bsi and no brake lights come on? If so, I'd definitely check the 6 pins plug in the lights. it might be that for some reasons the female blade contact in the plug got loose, thus not transmitting power to the receptacle. Strange that it happened on both sides but nevertheless if you have power with the plug removed, and none with it inserted, the problem has to lay in the plug itself. Check continuity from the connector to receptacle when plugged.

[barrymurphy]

Yes, my next move it to remove the tail light and see whats happening. Its very strange. Thank you for your assistance so far.

I will update you when I have done this, probably this evening.

I think, based on the testing so far, I can rule out a BSI issue.

[barrymurphy]

Would you happen to have a wiring diagram for the licence/number plate lights? On my car they are attached to the right hand light cluster and it looks a bit rough and as if someone had repaired it? I thought this could have something to do with my issues but then it could not affect both sides.