I seem to remember other posts - three I think - with intermittent light failures that are unresolved.

Well add one to the list.

My left xenon light occasionally fails to light up - but after a few off-and-on switchings does come on.

There sometimes is a bulb failure indication in the instruments and sometimes not. When turning the engine off, the failure indication disappears.

Two weks ago, the dealer replaced the xenon bulb, but that was apparently not the problem.

It seems only to happen on initial start in the morning or when the car has been stopped, such as after shopping, not when switching on the lights when driving.

My only thoughts at the moment is that the battery voltage (I have not measured) is lower when starting up than when driving, so it could be voltage related.

I have asked the daler to check with Skoda for any known issues - asking the Danish importer is probably a wasted effort.

If anybody gets any clues as to the source of the problem, please do tell.

Edited 8 January, 201016 yr by Agerbundsen

My demo car did this once and I know of one other that has done it.

Our technicians are looking into why it occurs, it's pretty hard to replicate but it seems to have something to do with having your lights on the 'auto' setting.

I have a problem with the HID on one side of my Jaguar. A local garage said it was the ignite, changed it and it still did the same thing. What happens is it sometimes lights up and then goes out or it takes lots and lots of switching on and off or sometimes, changing the combination of engine on first then light or ngine off then light. You manage to ignite it but after 5 minutes it goes off again and stays off. Nobody on the jaguar Forum had any answers so I guess it is a programming fault at the main dealers.

My demo car did this once and I know of one other that has done it.

Our technicians are looking into why it occurs, it's pretty hard to replicate but it seems to have something to do with having your lights on the 'auto' setting.

Hi James,

I am glad you are on to this. As I see it, one diagnostic problem is that the fault ligt goes away when you turn the car off, so getting it to an analyzer while the fault is showing is difficult. It gets dark here at 1600 and the workshops close at 1600.

I am not sure if the clue regarding the supply voltage is valid or not, but it is a clue.

There is no "auto" seting on mý car. You can get the complete vehicle codes on it in a different thread if intersted.

if I learn any more, I will post.

Edited 7 January, 201016 yr by Agerbundsen

Interesting you don't have an 'auto' position, Agerbundsen - that's just blown my theory into the weeds!

From my days with aircraft we had issues with some of the more complex types with lots of computers; bogus error codes due to one computer not talking to another computer as quick as the first one expected on start up.

Therefore first one had a dizzy fit throwing up an error code for a system that besides being a tad slow to wake up was otherwise working fine. :S

TP

From my days with aircraft we had issues with some of the more complex types with lots of computers; bogus error codes due to one computer not talking to another computer as quick as the first one expected on start up.

Therefore first one had a dizzy fit throwing up an error code for a system that besides being a tad slow to wake up was otherwise working fine. :S

TP

We have an easier life - we don't have computers on our aeroplanes, they just find other cunning reasons why they don't want to fly :yes: !

We have an easier life - we don't have computers on our aeroplanes, they just find other cunning reasons why they don't want to fly :yes: !

To true aero,

you reminded me of an incident with our then Station Commander and a Hurricane which he claimed didn't want to take off.

Besides burnt out brakes (from several take off runs and aborts, which we were musing over back on the pan) she was fine and took to the air with no problem later that week with another pilot.

TP

To true aero,

you reminded me of an incident with our then Station Commander and a Hurricane which he claimed didn't want to take off.

Besides burnt out brakes (from several take off runs and aborts, which we were musing over back on the pan) she was fine and took to the air with no problem later that week with another pilot.

TP

Ah, the old problem with the knob on the end of the throttle then....!!

Ah, the old problem with the knob on the end of the throttle then....!!

:yes:

Interesting you don't have an 'auto' position, Agerbundsen - that's just blown my theory into the weeds!

Maybe not......

I just did a little test sequence:

Car off -turn lights to ON. Naturally nothing happens with the key out.

Turn key to on, but not far enough to start the engine. Both zenon lights fire up.

Turned key to start after two seconds - engine starts and left xenon quits.

Turn lights to off (=DRL position) wait a few seconds.

Turn lights to ON and both xenons light up and stay there, going through their usual little dance of looking down, then out and then up to normal position.

Did I duplicate what the "Auto" does?

It definitely seems to have a voltage relation, but why just the left one and never the right one? Battery is on the left of the car, so it is not line losses from longer undersized wires, me thinks.

I will plan to now only turn on the light after the engine is running - for some time and then switch to the other mode to see if the fault can be forced to happen.

...........the plot thickens.

Maybe not......

I just did a little test sequence:

Car off -turn lights to ON. Naturally nothing happens with the key out.

Turn key to on, but not far enough to start the engine. Both zenon lights fire up.

Turned key to start after two seconds - engine starts and left xenon quits.

Turn lights to off (=DRL position) wait a few seconds.

Turn lights to ON and both xenons light up and stay there, going through their usual little dance of looking down, then out and then up to normal position.

Did I duplicate what the "Auto" does?

It definitely seems to have a voltage relation, but why just the left one and never the right one? Battery is on the left of the car, so it is not line losses from longer undersized wires, me thinks.

I will plan to now only turn on the light after the engine is running - for some time and then switch to the other mode to see if the fault can be forced to happen.

...........the plot thickens.

Hi

I use auto lights and it is my offside headlight that goes out. It has been back to the dealers and they had it first for a week then a day and then a fortnight, I was then told to use the lights on manual until a fix was found. The light still went out, so mine is back in the dealers until they fix it. They taxed another one for me to use while they try to fix it.

So far I have noticed the same fault twice on this one.

Regards

Mike

That's very interesting, Agerbundsen. Looks like it could well be some form of power surge during engine start. I haven't has any problems when switching the lights to 'auto' after engine start. The three times I have had a problem (starting the engine with 'auto' selected) it has been the right hand light - our off-side, drivers side as with you.

Killy, I'd go and back your monster back and wait for a fix unless you want to keep the miles down on it! I reckon it'll be a fair time before someone comes up with a fix and it is likely to be from somewhere well above dealer level.

That's very interesting, Agerbundsen. Looks like it could well be some form of power surge during engine start. I haven't has any problems when switching the lights to 'auto' after engine start. The three times I have had a problem (starting the engine with 'auto' selected) it has been the right hand light - our off-side, drivers side as with you.

Killy, I'd go and back your monster back and wait for a fix unless you want to keep the miles down on it! I reckon it'll be a fair time before someone comes up with a fix and it is likely to be from somewhere well above dealer level.

Dead right Aerofurb. I'm going to sit tight and wait for "THE FIX" . I will report it to my dealer and wait. Its not a deal breaker and I dont need the stress of running around swapping my monster for a hire car. They will sort it out.

Sorry - duplication.

Edited 10 January, 201016 yr by Agerbundsen

This is not quite a statistically valid test, but I have for two days now used a technique to test the light problem. I start the car with the lights off and then turn them on. Not just several times in a short time, but in normal use of the car. It has been about 10 times, and the lights have come on immediately with no hesitation at all - each time. No failures and nothing else.

It seems to support the idea that the problem is low voltage related.

to be continued...............

Have I got this right;

when you turn on the ignition with the lights in Auto or Dipped Beam one of the Bi-xenon headlights goes out and if so do all who are effected have the same light go out?

Does it effect any of the tail lights in the same way?

TP

Have I got this right;

when you turn on the ignition with the lights in Auto or Dipped Beam one of the Bi-xenon headlights goes out and if so do all who are effected have the same light go out?

Does it effect any of the tail lights in the same way?

TP

It is so it is when not consistent - meaning it does not happen every time. It is only the left xenon light that fails, and it does come back on after some time. I do not have "Auto" , so it is when the headlight are in "on" position. Dipped or not is realy the same electrically from the light perspective - it is only a mechanical flp that makes it dipped. I have not specifically looked at the taillights, but I do believe they function normally with a failed headlight.

It is always the left (driver's side) light that fails to light.

In philosphizing about this, I cannot quite get myself to believe that the length of wiring differences between the two can have enough influence on the voltage. Since the light work OK with the engine running, I also cannot see that there could be a basic program fault. Since the bulb itself was replaced with no change, I suppose the "ballast" or coil, bringing the voltage up to the high voltage required has a problem, or there is some bad connexion (Yes that spellinge was allowed by the Oxford Concise Dic., but alas no longer used) in the harness, dropping the voltage during the initial firing of the light.

All of that is pure speculation so far.

I am keeping my dealer informed, but have no real feel whether they are working on it with the importer, who is not too helpful, generally, or just ignoring it till I insist on some action.

Thanks Agerbundsen,

the linked article is very heavy going but it does describe the operation of the HID HEADLAMP BALLAST CONTROL IC, which I think could be part of the problem or responding as designed to a sensed lack of voltage.

My link

Anyway the following paragraph from the linked article make interesting reading:

[0027]Turning to FIG. 1, the first state that the IC will enter is the self test mode 500. In this mode the DC to DC converter section is enabled enough to produce a reduced voltage at the DC bus, which is then measured to establish that this section is operating correctly. In the event of damaged components being present in this section, the IC will shut down. Next the high side switches of the H-bridge section are both switched on after having pre-charged both bootstrap capacitors DBS1 and CBS2. Voltage is detected at the mid point VS, of each side of the H-bridge to determine that the level shifting circuitry and high side switches are operating correctly. Next the high side switches are both switched off and both low side switches are switched on and the VS voltage is detected to ensure it has now dropped to OV. If at any stage the correct voltage is not detected the IC will shut down. During this phase the negative auxiliary voltage to the igniter is also sensed at ZH via divide resistors RZH and RZH1 to RZH4 to ensure that it is present. The negative auxiliary voltage is produced by winding 25 A of flyback transformer 25 and rectification by diode DC3. After passing the self test mode, the IC will enter the pre-ignition mode 502, in which the DC bus voltage is raised to ignition level. At this point if the ignition does not occur within a set time, the IC will shut down. Additionally, if the IC has attempted unsuccessfully to ignite the lamp more than a specified number of times, then the IC will again shut down

Read more: http://www.faqs.org/patents/app/20080211425#ixzz0cEEvevDZ

Unfortunately haven't found the diagrams mentioned, which are always useful.

Hope that helps,

TP

It's my right headlamp that has sulked - and only when starting the motor with the lights in 'auto'. Not known of a rear light snag at the same time, didn't look but no warning light indication.

I'd agree about it being a power supply issue be it low volts or a power surge causing it to not play the game.

I did a little surfing, and find that similar problems - and lack of definitive solutions - exist on forums for BMW, SEAT, Mini2, Jaguar, Mercedes, Renault and Volvo.

Of the replies that make sense to me, the following sources have been cited:

Voltage drop from starting both the engine and xenons simutaneously.

Undersized or bad battery.

Non-seated fuses - separate fuse for each side.

Wiring faults, such as poor crimping of connectors.

Bad grounding of the xenon bulb/housing.

Faulty started/ballast.

The following explanation of the xenon lights may be easier to follow than the Patent:

"Because of the energy required to run a HID headlight, the HID bulbs do not run on low-voltage DC current, so they require a power pack (ballast) with either an external or internal ignitor, which controls the current given to the bulb. Considering automobiles use a 12-volt electrical system for their lamps and the HID lighting requires over 20,000 volts to ignite the bulbs and then 85 volts to keep them running, the ballast is a necessary part of the system. Apart from turning it on it also regulates the voltage, and is an integral part of the HID system.

The power-up of the bulbs happens in three phases. First comes the ignition, when a high voltage pulse is used to produce a spark which ionizes the Xenon gas, creating a tunnel of current between the Tungsten electrodes. After this comes the initial phase, when the temperature in the bulb capsule rises rapidly, the metallic salts vaporize and the resistance between the electrodes fails.

The ballast comes into function and automatically switches to continuous operation, when all metal salts are in vapor phase, the arc of light has achieved a stable shape and the luminous efficacy has attained its nominal value. Being supplied with stable electrical power by the ballast, the arc will not flicker. "

I experience the failure as the initial spark and bright flash does take place, but then the light fails. This seems to be consistent with low voltage during start of both engine and light.

It may be a timing thing. The headlights switch off during engine start to give full power to the starter motor, perhaps the lights are trying to come on when the starter motor is still turning?

Another article on ballasts but with diagrams if you open the PDF link at the beginning.

My link

Not noticed any light issues on the Superb or Octavia forum but they don't use Bi-Xexon

TP

It may be a timing thing. The headlights switch off during engine start to give full power to the starter motor, perhaps the lights are trying to come on when the starter motor is still turning?

Could be. Then if you switch on the car in "auto" and wait till the xenons are finished their littel dance and are fully functional, and then start the engine, the fault may not be there? I do not have the time now, as >I am cooking supper, but it should be tried.

Intermediate update.........

Dealer called today: Your Yeti is missing an update to the controller software. We will fix that. No details, but my assumption is the lamp start should wait for the battery voltage to be back up after engine start - or delay the lamp start during engine start. Good thing is that they have worked it though the info system and received some accept that the problem is known and there is a suggested fix.

At the same tme the smell of diesel exhaust was discussed. Apparently there are some rubber flaps relieving pressure in the car when shutting the back doors, which may stick and let exhaust into the car - we agreed to let me document the situations better and then try to fix both at one time.

Positive: The problems are being addressed at the proper level.

The saga continues..................

Edited 13 January, 201016 yr by Agerbundsen