C5 headlamp wiring

[swiveleyedgit]

Hi all, trying to pin down a problem with the nearside dip beam on my C5 MK1, does anyone know where the feed for it is located? The book of lies shows the feed for both dip beams comes through the same fuse in the engine bay fusebox and then splits for each lamp but I can't find where the split is. I need to check the continuity of the cable, every other lamp in the cluster is working and the bulb itself is good. Any pointers gratefully received .

[BX]

My book of truth says otherwise.
There are 4 fuses in the engine bay fuse box BM34.
F9 left hand dip beam
F10 Right hand dip beam.
F11 Left hand main beam
F12 Right hand main beam.

The LEFT hand dip beam is wired as follows.
From F9 to pin 15 on the 16 way GREEN connector on the BM34.
From pin 15 on wire 271 to pin 3 of the black 6 way connector of the headlamp.
Most Citroën wiring looms have the wire numbers printed on the insulation every few cm along their length.

For comparison purposes the right hand dip is pin 8, wire 272, to pin 3 in the right hand headlamp.
The same relay contact feeds both F9 and F10.
The connectors on the BM34 are a common failure point for high current users such as the LP fuel pump and the heater blower. Treat the headlamp connections at the fuse box with suspicion.
All the above assumes you have standard halogen headlamps.
H4 bulb for main beam and fog light. (dip filament used for fog light)
H7 bulb for dip beam

[swiveleyedgit]

Yes BX you are right, a seperate fuse for each lamp, don't know why I wrote that..... turns out it was the 'one bulb blowing and taking the other one with it' problem. I managed to replace one blown bulb with the blown one from the other lamp, I claim insanity and senility. Anyway, I've replaced both dip beams with Osram Nightbreakers now, they're a big improvement on the standard bulbs I must say. Also managed to do it without taking the front of the car apart, which was nice. Thanks for the info on the bm unit, I've noticed the headlamps occasionally flicker so I may have to have a closer look at the wiring sometime.

[myglaren]

The headlight flickering is normal - normal for a C5 anyway.
Attributed to the suspension pump cutting in, that draws a large current.

[swiveleyedgit]

Thanks Myglaren, that's reassuring to know. On a related note, I've tried adjusting the nearside dip beam, it's pointing about 15 feet in front of the car, to no avail. The adjusting nut turns ok and I can see the gears working but nothing much seems to be happening. I think it may have move a little but I can't be sure. What exactly is supposed to move when you turn the adjuster? Looking in the headlamp as I turn it doesn't give me a clue. Broken? or am I missing something?

[myglaren]

Sorry, can't help there as I have never had to make any adjustments, even when I fitted new headlight units.

I did keep one of the old ones for ages but dumped it recently.
I don't know if they are the same but I have a pair of Xenon headlamps somewhere to, If I haven't chucked them as well
will have a look around.

[swiveleyedgit]

I think the xenon lamps have self leveling mechanisms on them, mine are just the ordinary halogen ones.

[jgra1]

Ah Steve I forgot completely about the xenons

[THELABMAN]

I've often wanted to fit upgraded headlight bulbs to my C5 but it seems to eat them at a phenomenal rate so I've been sticking in heavy duty ones from Halfords which are lasting ok.... mind you maybe I've just been fitting crap quality bulbs as it's usually Halfords I go to and get them to fit them.

[Northern_Mike]

I've replaced one headlamp bulb in 5 years in the Berlingo. I think I did one in a Xantia back in 2008.. brake lights I seem to replace one or two a year. Never had one blow in a C5. My brothers had my old C5 for 4 years now and it's not had any new bulbs at all while we've owned it.

Sent from my SM-N9005 using Tapatalk

[Peter.N.]

I had this problem with my 406, eventually fitted a relay switched by the other lamp.

Peter