Headlights Dimming/flickering Whilst Driving

[MichaelDavis]

Has anyone managed to find out what causes the headlights to randomly dip whilst driving? I have checked all earth's and checked tightness of battery connection, lights don't flicker when car is stood still with engine running from what I can see.

[paul.h]

By dip do you mean the lights go dim ? On the C5 it may be related to the suspension pump running and taking a high current. You could check the battery voltage before starting the engine and once running to see if the battery and charging are in good order. If the pump needs to run frequently then maybe there is a suspension problem - are there any leaks, does the suspension sink with the engine off, is the lds fluid level correct ?

[coastline taxis]

And thats exactly what it is paul. every time the pump makes an alteration the lights flicker due to the current been drawn and then the lights go back to normal when the regulator on the alternator compensate for it

[MichaelDavis]

No leaks and car doesn't sink. So basically it's normal? Battery charging fine.

[coastline taxis]

it does its just that you dont notice it. im not talking inches here. every time the ride height adjuster is moved it tries to correct it back to the correct ride height. this includes speed humps and pot holes

[paul.h]

Sounds normal, I do not really notice the lights on our C5 going dim except sometimes when parking it on the drive and the lights are shining on a wall.

[MichaelDavis]

It's very noticeable on my car and passengers have noticed it too - one commented are your lights going to go off! I said no it does this all the time. I did read somewhere that someone else had this problem and they changed their alternator which fixed it, another person changed the battery which fixed it but then someone else changed battery and it made no difference. My battery is the original and as the car is 10 years old in February next year it has done well. I've had the car just over 3 years and the lights have always dimmed whilst driving along never when stationary with engine ticking over.

[coastline taxis]

check the earths and feed wires to the headlights then

[MichaelDavis]

Ok will do thanks

[paul.h]

I would also check the battery, it may not have enough capacity left to run all the electrics and the suspension pump without the voltage dropping a bit. Maybe when it is doing it also have a look at the battery gauge on the dash to see if it drops a bit. I have found after about 7 years most batteries are due for replacing.

[MichaelDavis]

Will do Paul thanks

[MichaelDavis]

Had battery checked today, results were:

Voltage 12.59v

Measured 576 SAE(A)

Rating. 680 SAE(A)

 

Cranking voltage 11.73v

 

Charging

No load 14.38v. Loaded 14.07v

 

Was told battery is still good, am considering a new one though as it's 10 years old in January what do you think?

[coastline taxis]

Wouldnt hurt after 10 years and also allows you to rule a cause out

[MichaelDavis]

Fitted new battery yesterday and haven't noticed any flickering/dimming of headlights this morning so hopefully that's one fault rectified. Thanks to all for advice.

[MikeLane]

I've noticed this on my C5 (2005) but, as it lasts very few seconds, I've put it down to one of those Citroen foibles.

(Had to change my battery at 106Kmiles - and 10 years old - as a cell died, but still get this occasionally with the new one.)

Edited December 14, 2016 by MikeLane

[MichaelDavis]

A month on and still no flickering headlights plus another bonus - no faults codes found on a random computer diagnostics check- this is a first for me with this car it has always had codes for this or that. I'm starting to really like this car the more I fix it- I think it had a hard life before I owned it and got just basic servicing- just need to change all discs and pads and egr valve and thermostat housing to make it perfect I think!It still drives and brakes but not as smooth as it could be.