Xenon Headlights (2011 Mk4 Mondeo) - both failed at once?

[breamster]

Fastdruid said:

Have you got the swivelling headlights?

Having replaced a bulb in mine it did concern me that there appeared to be nothing special on the wiring to allow them to swivel. It concerned me that if it was located a bit wrong it would wear out the wiring in not that long.

Thanks. Nope. They don't swivel but they do auto level.

Fuse is only for the full beams, normal headlights still work as intended as does the levelling.

[Penelope Stopit]

I have searched and searched more for a diagram with no joy and without one things get difficult
There is a way that you can prove if it's a LH or RH headlight fault but it will take a bit of work and a diagram will help save much time
Has anyone access to a diagram for this car?

Are you able to get stuck in and do a bit of wiring to help prove what is causing the problem if a wiring diagram doesn't show up?

[breamster]

Penelope Stopit said:

I have searched and searched more for a diagram with no joy and without one things get difficult
There is a way that you can prove if it's a LH or RH headlight fault but it will take a bit of work and a diagram will help save much time
Has anyone access to a diagram for this car?

Are you able to get stuck in and do a bit of wiring to help prove what is causing the problem if a wiring diagram doesn't show up?

Thanks for your efforts - I do appreciate it!

I've had a look as well and not found anything. Still looking. I am a bit wary of doing too much wiring - I have experience of burning insulation off of wires with nice puffs of smoke.

Presumably I could try unplugging one headlamp at a time and see if the fuse blows? If I put full beams on for a few minutes (in the drive) it should blow if it is going to. Would that help?

I've only just got home - dark when I leave for work and dark when I get home. I really don't like this time of year. Too late for me to try it tonight plus I am tooo tired. Will try it tomorrow.

Thanks!

[Penelope Stopit]

breamster said:

Thanks for your efforts - I do appreciate it!

I've had a look as well and not found anything. Still looking. I am a bit wary of doing too much wiring - I have experience of burning insulation off of wires with nice puffs of smoke.

Presumably I could try unplugging one headlamp at a time and see if the fuse blows? If I put full beams on for a few minutes (in the drive) it should blow if it is going to. Would that help?

I've only just got home - dark when I leave for work and dark when I get home. I really don't like this time of year. Too late for me to try it tonight plus I am tooo tired. Will try it tomorrow.

Thanks!

Yes you could try disconnecting one and then the other if need be, I take it you are sure that the units that power the bulbs are fitted to the back of the headlights, I would expect the units to be fitted away from the light units but I have been wrong many times in the past
If you have no joy with the above and by that I mean the fuse is still blowing, you could disconnect both of them and prove that it still blows when switched on and left for a while, at least you will then know for sure that the fault is not to do with the light units themselves and that there is a very good chance that there is an intermittent short on the wiring harness
If there is an intermittent short on the wiring harness and you can't get that short to come and go by doing a waggle test on the harness in the places that you can get to to pull on it, there is a very good chance that no professional will get the short to come and go by pulling on it and you could end up throwing money at a professional that perhaps is not professional enough to give you a 100% guaranteed fix
There is also a very good chance that the wire or wires that connect to the fuse that is blowing terminate to a relay or relays and whatever that scenario is at some stage will split for LH and RH headlights
I would expect a manufacturer to fuse the headlights, one fuse for LH and another for RH yet I have witnessed some major mistakes in harness design and have had to come up with a solution to put those mistakes right, so although I expect there to be LH and RH fuses my expectations could be proved incorrect

If it was my car and disconnecting both LH and RH lights, first one at a time and then both at the same time did not remove the short and a waggle test proved nothing I would do the following

1) Gain access to the back of the fuse-box and find out if there is one or more wires coming from that fuse that is blowing

2) If there are two or more wires coming from the fuse I would have no option but to cut those wires at a workable distance away from the fuse-box and fuse each wire independantly with in-line fuse holders and fuses. I would then check what current each wire was taking with the lights switched on and functioning correctly. In now knowing what the current consumption is for each wire, I would fuse each of those wires at a current rating to the closest fuse available that is just above the consumption figure found when testing, I would then uprate the main fuse knowing that it could not blow when the short came on, yet I would also be confident that when the short did come on, one of the inline fuses that I had wired in would blow and point me in the right direction to where the fault is

3) If I found that there was only one wire coming from the fuse that is blowing I would have no option but to trace that wire to a relay or whatever and find out where it splits for LH and RH lights and carry out the same procedure as I would have done if finding multiple wires from the fuse at the fuse-box
I would end up with inline fuses at another point along the loom (perhaps a single wire to a LH/RH split at a relay) and then wait for one to blow and that would point me in the correct direction to find the fault

This is why I asked you earlier if you could get stuck in with a bit of work to prove the cause of the fault.
You are unlucky to have the problem when leaving home and arriving back in darkness. You are lucky that the short is happening often and can be found, imagine if it only blew once a week for instance, although by fitting inline fuses a once a week blow would still point to the faulty wire/circuit

Have a think, if I could find a diagram things would be a touch easier, the above work is for a no diagram fix, with a diagram I could possibly point you to a quicker fix as in I would be able to tell you where to split for inline fuses rather than you having to check first at the fuse-box. A diagram will show how many wires are connected at the fuse-box and relays etc

Should you decide to pay good money for a fix, you may save some money by asking an enthusiast or good technician of some sort to do the above, don't pay good money for someone to play around in trying to get the fuse to blow when you have already done this, pay good money for a fix, no fix no pay or no fix a little money is the way forward

Edited by Penelope Stopit on Tuesday 15th November 10:35

[Beati Dogu]

breamster said:

Bum. Spoke to soon. Fuse has blown again. Does anyone have any ideas? .

Do what an electrical engineer friend of mine would do and use a bigger fuse.

[Penelope Stopit]

Beati Dogu said:

breamster said:

Bum. Spoke to soon. Fuse has blown again. Does anyone have any ideas? .

Do what an electrical engineer friend of mine would do and use a bigger fuse.

What's wrong? Are you bored?