Ford Focus Headlight bulbs

Alfrescodave

Son has a 2004 Ford Focus, 90,000 miles which is literally eating headlight bulbs.For the past 2 years he's had to replace 6 headlight bulbs, both nearside and offside.

Any thoughts as to what is causing this? (voltage fluctuation?) and what checks can easily be done to identify the cause.

TIA

n217970

6 bulbs in 2 years? Thats hardly "eating" and doesn't suggest a problem - even if there was a problem H7 bulbs can be bought for as little as £1-2. I bought one at a fuel station for £3 yesterday morning. The cost to "fix" it would probably be more then cost of bulbs the car will use in its remaining life time.

For whats its worth I had a Peugeot years ago that would easily go through six H7 bulbs in 1 winter alone, you get good at changing them.

atrixblue.-MFR-.

n217970 wrote: »

6 bulbs in 2 years? Thats hardly "eating" and doesn't suggest a problem - even if there was a problem H7 bulbs can be bought for as little as £1-2. I bought one at a fuel station for £3 yesterday morning. The cost to "fix" it would probably be more then cost of bulbs the car will use in its remaining life time.

For whats its worth I had a Peugeot years ago that would easily go through six H7 bulbs in 1 winter alone, you get good at changing them.

i would say this is normal either.


When replacing the bulb, you shouldn't hold the bulb in your fingers, oils of your hands can cause premature failure wear a latex or nitrile glove.


I would suggest looking in the manual and finding the fuse rating to see if anyone has altered the fuse to a higher rated one as a starter to make sure that someone in a previous ownership hasn't gone a put a higher rating in because this was an issue previously.


secondly, condition of the headlamp and its backing cover, any condensation in the lamps, rust on the connections, backing plates or dust covers missing exposing the electricals and its bulb to the elements?.


thirdly, Cheap bulbs don't tend to last although I would expect them to last more than what has been experienced here invest in a good set.

Ectophile

On the other hand, my Fiat panda has gone through zero headlamp bulbs in nine years. Car bulbs never seem to blow these days.

Has anyone checked the voltage produced by the alternator? It should be between 13.8 and 14.4V with the engine running. Any more than that means the regulator has failed.

EdGasketTheSecond

My H7's have lasted 50K miles / 5 years of commuting ( in the dark in winter). Bulb quality has a lot to do with it. If your son's car is not blowing other bulbs then there probably isn't a problem other than cheap low quality bulbs.

Alfrescodave

EdGasketTheSecond wrote: »

My H7's have lasted 50K miles / 5 years of commuting ( in the dark in winter). Bulb quality has a lot to do with it. If your son's car is not blowing other bulbs then there probably isn't a problem other than cheap low quality bulbs.

Quality of bulbs was our first thought but having bought expensive and cheap bulbs there doesn't appear to be much difference.

Good point about about other bulbs not being blown, could this suggest that voltage irregularities are not the cause or are headlight bulbs more susceptible to voltage changes?

Joe_Horner

Ectophile wrote: »

Has anyone checked the voltage produced by the alternator? It should be between 13.8 and 14.4V with the engine running. Any more than that means the regulator has failed.

Very much this. As a rule of thumb, a 5% over-voltage will halve the life of a bulb. That only needs the alternator to be putting out about 15v instead of nominal and that can happen just from aging of the regulator without actual failure.


eta: the problem is worse with headlamp bulbs compared to the rest because headlamps are often slightly "over-driven" anyway - effectively being designed as (say) 11V bulbs, labelled as 12V, then run on 13.8V (nominal) because a small over-volt gives a big increase in brightness (but also shortens life).

That's why headlight bulbs tend to blow more often than the others in normal use.

Alfrescodave

Joe_Horner wrote: »

Very much this. As a rule of thumb, a 5% over-voltage will halve the life of a bulb. That only needs the alternator to be putting out about 15v instead of nominal and that can happen just from aging of the regulator without actual failure.

Will definitely check this tomorrow

therealhyper

A loose connection in the lamp holder can also cause bulbs to blow. or if the spring loaded connection in the bulb holder is slightly loose.

marlot

I had a company BMW which blew one of the headlamp bulbs every 4-6 months. It was eventually tracked down to a poor connection.

facade

My Renault Nee-san goes through bulbs just as quickly. The charging system voltage is a tad on the high side, being over 14, but within spec. to the manual.

Fords always used to specify some secret special silver battery that costs a fortune, because they have a charging voltage over 14V too, but a normal cadmium doped lead acid battery is fine.

I agree with the OP, as I've never had to replace a headlight bulb before since we went from sealed beam units to H4, and now I buy osrams a half dozen at a time, and use 4 at least over the Winter.