bi-xenon replacement bulbs

[swells]

I’ve just bought a 2002 XC70 D5 SE with bi-xenon headlights, but one of the lamps is ‘whiter’ than the other. When I checked to see how easy it would be to replace the bulb, I saw the sticker warning about high voltages and only entrusting this task to a Volvo dealer.
Is replacing a bulb that dangerous?!

Any advice would be most welcome.

Steve.

[AWD*V70XC]

Xenon is a gas within the bulb which when it is 'charged' it produces a brighter light, but this is also due to the use of 'mirrors' within the light surround. As with halogen bulbs you must not touch the glass of these bulbs as the salts from your fingers will penetrate the glass and you could find yourself replacing the bulbs within hours.

It is possible to do it yourself (and it will be cheaper) but I would ask one question first, "why is one brighter than the other?" My theory is a faulty module which would repeat the results if you change the 'duller' bulb. Headlamps are wired in what is called a parallel circuit where each lamp receives full battery voltage. However, if your car is of a newer model with daytime running lights and the headlamp high beams are used, there's a second circuit controlling them through an electronic module. The high beams could be wired to the module so that they can be fed current for DRLs in a series circuit–the current flows through both, so that one acts as a resistor for the other. The result is less brightness, but also less current flow for reduced power consumption. If you have a problem with the high beams, a defective DRL module is one of the new possibilities of which you should be aware, both for sealed beams and replaceable bulb designs.

I think I smell money pouring into the dealers bank account.

Keep us informed of any results you find.

[Puff The Magic Wagon!]

He's just bought so fingers X'd for warranty...

[RedXC]

Xenon is a gas within the bulb which when it is 'charged' it produces a brighter light, but this is also due to the use of 'mirrors' within the light surround. As with halogen bulbs you must not touch the glass of these bulbs as the salts from your fingers will penetrate the glass and you could find yourself replacing the bulbs within hours.

It is possible to do it yourself (and it will be cheaper) but I would ask one question first, "why is one brighter than the other?" My theory is a faulty module which would repeat the results if you change the 'duller' bulb. Headlamps are wired in what is called a parallel circuit where each lamp receives full battery voltage. However, if your car is of a newer model with daytime running lights and the headlamp high beams are used, there's a second circuit controlling them through an electronic module. The high beams could be wired to the module so that they can be fed current for DRLs in a series circuit–the current flows through both, so that one acts as a resistor for the other. The result is less brightness, but also less current flow for reduced power consumption. If you have a problem with the high beams, a defective DRL module is one of the new possibilities of which you should be aware, both for sealed beams and replaceable bulb designs.

I think I smell money pouring into the dealers bank account.

Keep us informed of any results you find.

I totally agree what you wrote! I just install mine with aftermarket. It is brighter than Volvo stock bi-xenon.

[swells]

Thanks for the replies, and to keep you updated:

The following day, the ‘whiter’ of the two lamps failed completely. The dealer tried replacing the bulb (£75.00), but still no light. Apparently it was the resistor module that had failed (unsure of the price, but the dealer – a non-franchised garage – was muttering about having to spend more than £200 in total).
Fortunately for me it was all covered by the warranty. In my research though, an HID bulb supplier (hids4u.co.uk) offered the following information:

“It sounds like you have one new and one older bulb. Older one being blue. It’s quite normal as the bulbs go bluer with age.
All you need to do is replace the bulbs together with either 2 yellow ones (4300K) or 2 6000K whiter ones.

Bulbs are approx 100 pounds a pair from me compared to 100 each at the dealer”

Quite useful information, really.
Now, are bi-xenons supposed to be self-levelling? Mine don’t appear to, but they do rotate upwards when on full beam, indicating that the motor is OK but that the self-levelling device is maybe at fault. Is there any way of checking this? And where is it located?
To help prolong the life of the lamps (and the modules), does anyone know if it’s possible to turn off the day running lamps? In my previous V70 there was a switch, and in older models a fuse could be removed, but there isn’t a separate fuse listed for the DRLs on this model.

Again, any advice would be most welcome.

Steve.

[Art]

Steve,

From what I understand, the self levelling feature or automatic range adjustment of the BZ lights is dependent on the load conditions of the car. The motors on the reverse of the headlamps are controlled by a position sensor located at the rear axle. When the sensor detects a change in the angle of the car under load, it sends this information to the CEM (central electronic module) which determines whether or not the lights need to be raised or lowered.

Deactivating the DRL’s would require a visit to the dealer.