The world has gone mad. until fairly recently to make your car headlights come on you would flick a switch. This simple act would connect the 12 volts from the battery to your bulb, which by the miracle of electricity would come on and you could see the road ahead. Simple but effective, it served the motorist well for many decades, the world was a happy place. This happy day scenario wasn't good enough though and what with us being in the computerised age some clever sod decided that the level of complexity needed to be elevated by at least 20 levels. Wouldn't it be nice, they said, if instead of using a standard incandescent filament bulb we used a high intensity discharge bulb like used in strobe lights but flash them so fast that they look like a continuous light source? Hmm, said the bosses, wouldn't that need a 1200 volt source and a complicated little box to make that happen? Oh, yes, said the engineers, but we have a whole load more ideas too. How about we make the lights go up and down with the suspension and also have extra lights that work with the steering so you can see round corners. And while we are at it instead of having two bulbs we could have a really complicated shutter sort of thing to give us high and low beam. We could use that low cost LIN bus, which could then talk to the CAN bus so the whole shagging caboodle can then be controlled by software in the body control module. Fuck it, while we are at it we could add an overly complicated monitoring system too and instead of calling them headlights lets call them AFL - adaptive forward lighting.
And that my friends, is what we have now, a wonderfully complex system that works beautifully right up until when it doesn't. Then you have a bit of a nightmare on your hands, particularly if you own a Vauxhall Insignia. Now not all Insignias have this, some of the more lowly models had standard halogen lights, the higher spec models though have xenon with all the added complications. To make matters worse somebody with a wicked sense of humour fitted the control module - or ballasts as they are called - to the underneath of the headlamp. It must have sounded like a good plan but what happens is that after a few years the headlamps start to allow water in, that water condenses, runs down the inside of the light and finds it's way in to the ballast unit. With 1200 volts flying about the place and electricity and water being sworn enemies it doesn't take long for shit to happen.
This problem is very common indeed, so much so that original headlights are now in very short supply and prices are absolutely ridiculous with 700 quid not being unheard of. It was therefore a bit of a shock when the bloke I brought my car off called me to say that both headlights had failed - 1400 quid to repair a car that had only cost twice that was a bit shocking.
It was then I set about determining what my options were, first thing though was to get the car through the mot and work out if there was anything else wrong with it and whether it was even worth bothering with. That little problem was solved by the dealer borrowing a couple of lights off another car and putting them on my car. This worked a treat and the mot went through with no advisories - result. Now I had to work out how to fix my lights so I could actually use the car.
I quickly found out that the original ballasts are German made by Hella, part number 5DV009720-00, there are several units that look the same but it has to be this specific part number. The rather surprising bit is just how expensive they are with a pair costing anything up to about 300 quid. Bugger that for a game of skittles. Now, the enterprising Chinese make what they claim to be copies that can be had for as little as 17 quid, trouble is while they make the lights come on, that's about all they do. You will still get an error on the dash because the cheap bastards couldn't be bothered to copy the whole circuit, they basically just do the high voltage generation bit and the shutter control. Rather annoyingly you will still get the error on the dash even though the lights will basically work. There appears to be about 20 different manufacturers of replacement modules, it is not clear if they are all the same and I'm not going to but one of each to find out so these comments are generalisations but looking at the feedback customers have left, it seems that just about every cheapo controller has the same problem, only the mega expensive genuine Hella ones seem to be guaranteed to work fully and correctly.
All this complexity to control just one headlight.
The bulbs themselves are pretty cheap these days, they were really expensive when they first started using them but you can get a pair for under 20 quid now and there is no doubt they give much better light than standard halogen. Fortunately it's quite easy to repair the headlight housing so that they don't leak any more, gentle heat will dry them out, silicon sealant will seal them so they don't let any more moisture in and contact cleaner will remove any light corrosion to the terminals, any heavy corrosion will still make your day a bad one. A cheap controller will give you your lights back but will leave you with that annoying message on your info display. if you are really luck you can use a Dremel or similar to open the module up like in the photo above and dry it out thoroughly. You can then reseal it and maybe, just maybe, everything will come back to life. Obviously you should not even contemplate such a thing if you are not confident to mess about with 1200 volt signals that can prove fatal in the wrong hands.
One other thing to be aware of is that at power up time the headlights do a self test, which involves making sure the Lin bus nodes are alive and that everything appears to be well, any fault puts the lights in to a default mode where only the low beam will work. Many folk believe this is as a result of a faulty bulb but forget the bulb is the same one for both low and high beam so if low beam works the bulb is definitely ok.
There is also another module involved, the AFL module, it's not entirely clear to me yet exactly what this module does and which functionality is in this module and which is in the ballast, it's so ridiculously complex and most information I have found so far is hard to verify, as things become clearer I will update this page.
My plan is to fit a cheap ballast - not one of the cheapest but one that is less than the Hella one and see how I get on, the supplier I have chosen seems to have good feedback, nobody seems to be complaining about error messages after fitting one. I am highly doubtful that it will work fully but at least it will give me headlights until the Spring when I can revisit the issue in comfort. I will update this article then and revisit any inaccuracies that get exposed during my quest - the info herein is just what I have found out so far and is subject to change as I go through the learning process.
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