C5 (2002) Headlamp flicker

amjake · Unread post by **amjake** » 26 Sep 2010, 12:40

Hi All,

I have noticed this in past but never had much need to drive in dark since owning car.

However this morning on return from Gatwick inearly hours, noticed that headlamps flicker quite a bit.

Not related to bumps, undulating surface, cats eyes or studs etc.

When they do flicker its always a double ie. flicker and 1-2 secs another.

Anyone one enlighten (no pun intended!) or advise?

Cheers

Kev

Unread post by **myglaren** » 26 Sep 2010, 12:48

A common 'problem', they all do it.
The dominant theory is that it is when the suspension pump cuts in. I'm not convinced

Xenon headlights may not be affected

coastline taxis · Unread post by **coastline taxis** » 26 Sep 2010, 12:49

I belive its to do with the suspension pump kicking in and drawing power from the car then the car compensates for it hence the flicker

amjake · Unread post by **amjake** » 26 Sep 2010, 13:18

Thanks for replies.

I had changed one set of bulbs, main beam to Xenons and now ordered another set for dipped as they seemed yellowey!

Let's hope that solves it or is there a fix?

Kev

rabenson · Unread post by **rabenson** » 26 Sep 2010, 17:26

definitely the suspension pump as coastline says - perfectly normal but b...y irritating!

Citroenmad · Unread post by **Citroenmad** » 30 Sep 2010, 17:42

Yes, it is the suspension pump cutting in and stealing power. I find some C5s do it more than others do, odd.

cachaciero · Unread post by **cachaciero** » 30 Sep 2010, 20:58

Citroenmad wrote:Yes, it is the suspension pump cutting in and stealing power. I find some C5s do it more than others do, odd.

Possibly some of the connections to / within the injection relay unit have a little higher resistance than others.

However I suspect that it may well be a measure of how good the battery is. The pump cutting in will take a lot of current it is fused at 50A but starting peak may exceed this, while the alternator will take up the load it too will have a lagging response time.

In my case for a while now one of my HIDS has kept cutting out then one morning the car wouldn't start, battery down to 10V, well it was at least four years old. Changed the battery HID's now stay on.

A trawl through the web will show other similar cases where changing the battery has effected a cure. Worth checking battery volts with lights on but no engine running anything less than 12v after five minutes on the battery terminals should be regarded as suspicious.

cachaciero

HDI · Unread post by **HDI** » 30 Sep 2010, 22:38

Almost certainly a tired battery as mentioned. I have a Mitsubishi Evo 6 with an HID conversion, proper Cibie kit. They would flicker without any related issue and I spent ages looking for poor connections, earths, bulb holders etc, without success. Then earlier this year when I put the car back on the road for summer the starter was very lazy at first start up, tested the battery and it was very tired. New battery fitted, end of HID flicker !!

Citroenmad · Unread post by **Citroenmad** » 01 Oct 2010, 06:58

The battery on my VTR C5 seems quite slow, these colder mornings are showing that. It was slow last winter but as the weather warmed it has been fine. I should replace it , though i might replace the car. However the C5 SX with a good battery shows up flickering headlights more. Probably down to the alternator.

amjake · Unread post by **amjake** » 07 Jan 2011, 21:47

Latest Update

Changed battery put on new Bosch Silver Plus and guess what lamps still flicker.

Garage has another theory and will keep you updated on result!

birstall · Unread post by **birstall** » 07 Jan 2011, 23:04

Here's a good story to keep you guessing.

My HID nearside beam turns off for about a second after driving for about 15 minutes or so. It then alternates on and off about 5 times for about a 1 second cycle. Then it switches off completely. This is only the nearside light, the offside continues to operate normally. The nearside light then stays off for as long as I continue driving.

However, if I then turn off the ignition and turn everything on again, the bulb returns to normal. Not only does it return to normal, but it continues to operate normally then no matter how far I drive after the restart.

I suspect that the damn computer is possesed with a malignant demon!

Or it may be some malicious code that a disgruntled software engineer hid in the programming.

Anyway, I'd be interested to know if anyone else has experienced the same.

dp · Unread post by dp » 28 Jan 2011, 17:31

birstall wrote:Here's a good story to keep you guessing.

My HID nearside beam turns off for about a second after driving for about 15 minutes or so. It then alternates on and off about 5 times for about a 1 second cycle. Then it switches off completely. This is only the nearside light, the offside continues to operate normally. The nearside light then stays off for as long as I continue driving.

However, if I then turn off the ignition and turn everything on again, the bulb returns to normal. Not only does it return to normal, but it continues to operate normally then no matter how far I drive after the restart.

I suspect that the damn computer is possesed with a malignant demon!

Or it may be some malicious code that a disgruntled software engineer hid in the programming.

Anyway, I'd be interested to know if anyone else has experienced the same.

I experienced something similar. It was corrected by the replacement of the headlamp bulb.

HTH
David

cachaciero · Unread post by **cachaciero** » 28 Jan 2011, 21:10

birstall wrote:Here's a good story to keep you guessing.

My HID nearside beam turns off for about a second after driving for about 15 minutes or so. It then alternates on and off about 5 times for about a 1 second cycle. Then it switches off completely. This is only the nearside light, the offside continues to operate normally. The nearside light then stays off for as long as I continue driving.

However, if I then turn off the ignition and turn everything on again, the bulb returns to normal. Not only does it return to normal, but it continues to operate normally then no matter how far I drive after the restart.

I suspect that the damn computer is possesed with a malignant demon!

Or it may be some malicious code that a disgruntled software engineer hid in the programming.

Anyway, I'd be interested to know if anyone else has experienced the same.

Yes mine has exactly the same symptoms sporadically.
Havn't worked it out but my belief is that the logic will detect a failure of the lamp or to be precise the supply to the lamp and initiate a "re-light" sequence it appears to do this for five times before giving up after which the supply needs to be removed from the controle box to reset the counter.
Now one needs to know why the lamp goes out in the first place having been successfully ignited and the only reason it can be is a break in current to the lamp, this is unlikely to be a failure in the lamp itself maybe poor connections to the actually lamp, failure of presumably semiconductor switch in the ballast unit, an other open circuit in the ballast unit. So far I have not worked out how best to measure any of this and the Lexia just gives up with the lamp controllers doesn't appear to recognize them and yes I do know that they have to be on when running the diagnostics.
I have observed that re-seating and or playing around with the wiring at the back of the lamp seems to improve it for considerable periods of time but then for no apparent reason it comes back.

cachaciero

wright · Unread post by **wright** » 29 Jan 2011, 00:08

I suspected I might need a new battery and then before Christmas during the cold weather i had to jump start it a few mornings, since replacing the battery I haven't noticed my lights flickering and they did before