2012 C4 Picasso Daylight Running Lights (Sort Of) Not Working

[yourguitarhero]

I have a funny problem with the DRLs on my C4 Picasso.

They used to work. You start the car and they are on, regardless of side- or headlights.
Now, they work, but only when the lights are set to sidelights.

What's weird is that I can go to the Daylight Running Lights option in the menus on the dash and there is an option to turn them on or off, but either setting makes no change? Still no DRLs without selecting sidelights.

Is there anything I can do?

[Dormouse]

Sounds like a relay/wiring problem. Do you have a fuse list showing the DRL circuit? I would start there in that fuse box. Has anything else started to misbehave or not work? Start with a cleaning of contacts and checking
/cleaning any obvious connections. If that doesn't work come back on.

[GiveMeABreak]

This behaviour sounds suspiciously like a setting has been changed in the BSI that changes the DRL operation. Has anyone been near the vehicle with Lexia / Diagbox lately since the DRLs have been operating like this?

[RichardW]

I would try a battery off first to re-set the BSI and see if that fixes it. There are various notes around about how to do a BSI reset, but really you just need to give it 5-10 mins after closing the doors before you take the battery off, leave it off for a minute or so, then reconnect, give it a few minutes to wake up, then turn on lights, then ignition, give it a min before starting engine. If this doesn't fix it, then probably needs to go on Diagbox to see if there is a clue - whereabouts are you in Central Scotland? I can't remember exactly, but I presume these come on bright for DRL function, then there is separate circuit for dim setting for sidelights, so it looks like the DRL function has gone away. This could be a computer glitch, or it might be a fault in the underbonnet fuse box. They're not required on a 2012 car, so it's probably not worth fixing unless it's a glitch!

[GiveMeABreak]

BSI Reset / Battery Disconnect / Reconnect Procedure

A note from the handbook for the relevant year for this model (build date July 2012):

LED Lamps
They come on when the engine is started.

Depending on the destination country, they are used for:
- daytime running lamps in day mode and sidelamps in night mode,
or
- sidelamps in day and night mode
Where LED lamps are fitted, the filament bulbs for the sidelamps in the front lamp units are not used.

[yourguitarhero]

Ok, I have figured it out!

The idea of "who had been working on the car" and "separate fuses" reminded me that I had removed the fuse from the "headlamp washers" (according to the handbook in the car). The screenwash pump fuse had blown when I accidentally triggered it in sub zero weather, the car had no spare fuses anywhere, and that one looked like the only superfluous fuse so had temporarily pinched it so I could see where I was going.
I didn't have any mini fuses lying about spare, so although having got hold of some, I had never bothered replacing the "headlamp washers" one.
Turns out it was for the DRLs!

[RichardW]

Quality!!

[GiveMeABreak]