Headlights still flickering

[nickd]

Hi all,

So, about 18 months ago my n/s Xenon bulb failed so I decided to replace both, with Osram night-breakers. A month or 2 after replacing them i noticed they had both started flickering, nothing too bad but a bit annoying.

Its got worse and worse over the past 12 months where it is probably borderline dangerous to drive at night. I did some research and understand it may be the ballast and not the bulbs at fault, so to try an narrow this down I replaced the n/s bulb last week (with the working original from when I replaced both). All has been well until last night when first I noticed the o/s started flickering and 30 mins later both were at it again.

Rather then going and buying new bulbs i'm going to try replacing the ballast but does anyone know if both sides need to be replaced at the same time? The flickering bulbs appear to be in unison so not sure if i replace one side if this give inconclusive results or if I should do both at the same time.

Thanks,

Nick

[SwissXC90]

What does VIDA report?

Both headlamps contain separate Xenon control units

It is statistically unlikely that both fail at the same time

The common points are items like power supply and grounding, make sure the grounding is good for both headlamps.
They ground to the top of the strut towers in the engine bay.
Those ground bolts are normally very tight, if any show signs of corrosion or oil etc, clean up the grounding points. But unlikely to be the issue.

The two headlamps are controlled by the HCM Headlamp Control Module, but this controls more the bending function of the beam rather than the Xenon lamp itself. The HCM is under the left front seat.

[nickd]

i haven't done a VIDA as I thought it would be the bulbs or ballast. Like you I thought I was strange that they had both gone at the same time and only after I had changed the bulbs. After putting the original bulb back in and still encountering the problems leads me to suggest something which controls both lights.

I will get a VIDA done and see what it says

[nickd]

Replaced the ballast on one side today and made no difference! Thankfully I managed to get one of Ebay for £50 rather then £350+ VAT from dealer.

Also checked grounding points and they look like new.

Now to check the HCM module's....

[SwissXC90]

The smart thing to do is check the diagnostic fault codes and the readings / activations using VIDA before you start coming to any conclusions or replacing anything.

Anything else is guesswork.

[nickd]

plugged into VIDA today and the error codes I got come up are:

• CCM-0040; AQS Internal fault - I will look to replace
• PHM-0030; reserve batt voltage low - explains VOC warnings
• REM-6A04; central lock motor switch signal too low - needs further investigation
• CCM-0061; Damper motor internal fault - need to investigate
• CCM-0062; Damper motor temperature left internal fault- need to investigate
• CCM-0063; Damper motor temperature right internal fault- need to investigate
• CEM-8A01; light switch faulty position - ??
• DDM-E010; control module internal fault - explains non working mirror
• HCM-6511; right hand lamp module (RHCU) voltage too low - ??

based on the above to cover off the 2 most obvious for CEM-8A01 I tried both dipped beam settings and they are just as bad. HCM-6511, only left headlamp control unit registers incorrect system voltage. The right headlamp is like a strobe. In a 45 second drive round the block, the right-hand headlamp flashed so much I got the bulb failure message (which is a daily occurrence but usually takes a while)

[Funky Diver]

Originally Posted by nickd

plugged into VIDA today and the error codes I got come up are:

• CCM-0040; AQS Internal fault - I will look to replace
• CCM-0061; Damper motor internal fault - need to investigate
• CCM-0062; Damper motor temperature left internal fault- need to investigate
• CCM-0063; Damper motor temperature right internal fault- need to investigate

Don't bother replacing it unless you can get a genuine one rather than Chinese copy. It'll give you no end of bother, particularly with internal cabin heating and that'll throw you right off the scent!

Just leave the one you have in (unless you're minted of course, but then I doubt you'd be using VIDA to diagnose the faults if you were lol) until you get a decent second hand one for cheaps.

You will possibly find you have a chinese clone in ... look for errors on the Lin-bus in Unrelated CSC's (I think). If you have it could well be the AQS that's causing all the CCM errors regarding heating.

So far as the other CCM's it's also very likely the thermistor in the little grill is knackered. Swap that out and it'll cure the errors, and it's cheap to do too (so long as you can solder!!)

[nickd]

I cleared the errors and only the AQS comes up, so will leave for a while on keep an eye on ebay.

All the heating works fine, quick to warm up, must be an older code!

[doingitsideways]

The battery low fault is likely causing your flickering lights.

The regulator has given up on my alternator, meaning system voltage dropped right out.
Xenons will flicker with low voltage. Mine were a little.

Maybe plug back into Vida and keep an eye on system voltage for a while, see if any drop when the lights start to flicker.

[nickd]

The low battery is the Volvo on call.

I did monitor the voltage and was always around 14.1 to 14.3