Help with headlight bulb question....

Evening all, Seems as soon as I start doing a few jobs on the old girl then its one thing after another..... got home tonight to find that my dipped beam was out on one side. having taken the headlamp assembly out I found much to my surprise what looks like a xenon or a litronic bulb assembly..... this is strange as the car was not specced with these so had assumed it would be the easy job of simply taking out a bulb and getting it changed. I've attached a picture of the bulb assembly which is labelled H7M 35W 6000K. Presume this is all one sealed unit with the two wires attached and connectors (could see no way this came apart). I looked at both bulbs and visually they looked the same, did not swap sides over as they are quite firmly gelled in to the units currently. There did seem to be a split second bit of light when the dash switch was moved but then nothing. is this indicative of a failing bulb of this type? other thing of note was that one of the spade connectors was out of the block, put this back twice and reassembled but no joy. Not sure this is anything to do with the dipped beam xenon/litronic as this seems totally standalone as an assembly. Looks then like I need to buy a new assembly. Anyone have the same set up and can recommend a source? best to buy both sides at the same time? if a new assembly does not cut it then its auto-electrician time I guess!! Thanks in advance for any advice. MOT in 3 weeks so need to get that sorted ASAP. cheers, giles.

Searching on this set up seems to suggest this is an HID upgrade. do we know if buying the bulbs from any source will come with the necessary connectors present already on the 911, i.e. are they industry standard?

If you have Litronic headlights (dipped beam has a bulls eye lense) the bulbs should be the D2S so you shouldn`t have H7 bulbs, if you have stock open reflector lenses then a previous owner may have installed a HID conversion it may be just the bulb that has failed or it maybe the ballast unit the only way to tell is to switch the bulb to the other side or try a new bulb if that doesn`t work then its the ballast so switch that as well to test. The bulbs as you say are 35 watt 6000K H7M the connectors are standard, I have never heard of a H7M before they look like they are a normal H7 HID which doesn`t give a good beam pattern I was advised to use H7R bulbs they are shorter and partially masked to cut light scatter and are more suitable for the open reflectors in the Porsche. The H7R bulbs and 35 watt ballasts are available online from HID suppliers but are cheaper on eBay, incidentally the 6000K bulbs have a slight blue tint but the 5000K give a whiter light but the bluer the light the less efficient the light. * * Del.

2004 C4S would have projector lenses as standard, but you don't have the standard (big square) power-connector for Xenons (because the connector is different - view this to see difference: https://www.manualslib.com/manual/392504/Porsche-911-Carrera-2003.html?page=226#manual H7Ms are Xenon bulbs, though, so all a bit weird. That lettering on the label implies an after-market kit to me, too. I really recommend [email removed] ; really helpful at providing good advice and have discount codes for good prices (25% OFF STOREWIDE - Terms Apply* Voucher Code: HNY20/HNY25) Personally I think it's just the bulb (a L-R swap would be the easiest test), but cannot be sure.

Del, that's great and much appreciated. given I'm a complete numpty around electrics when you say switch the ballast unit and the bulb..... The 'bulb' seemed to be a sealed unit with the connectors on, I'm assuming you mean switch the entire assembly when you say bulb. The ballast unit is presumably inside the headlight recess somewhere and the only bit I've seen is the 2x connectors which plug into the 'bulb' assembly? Sorry likely a stupid question. I may well pull the bulb units out tomorrow evening and switch these over as you say. The car goes to my Indi on Fri am for the weekend/Monday for new brake lines and 48k service (atleast I hope that's all...) so I may get them to look alittle further if the bulb assembly swap does not fix it. Once confirmed and if new bulbs are needed then are ebay sources of decent quality? I see Design 911 want quite a lot for the 2x bulb assembly so I guess its cheaper to go elsewhere. Also need to polish my headlights again to help I think! thanks again for the great advice. cheers. giles.

EGTE, Great many thanks also. This must be a HID upgrade (and I'm thinking the previous owner may have mentioned something in passing). No washers on the lights which I think may have helped indicate factory litronics....? I'll swap over the bulbs and see where we get to. if that's sorts it then I may just buy a new pair as presume they lose power with age and they look to have been in their some time! They are fiddly bastards to get at, light removal a sinch but the units when opened not great for fat hands. if my attempts tomorrow don't shed light then I may pay the indie to spend an hour looking into it. I'll also check out the website you linked as seems I may have a weird set up.... cheers, Giles.

If you have Litronics the bulb should be D2S and should connect to the ballast which should be fixed to the headlight, the H7R HID bulbs on eBay are the same as the bulbs from online dealers just cheaper but if you have H7 bulbs you haven`t got Litronics which should have headlight washers also the D2S and H7 bulbs are different one won`t fit the other. If you do need H7R bulbs get the metal flange versions - some have a plastic flange. * * Del.

Perfect thanks. seems we've all agreed I have an HID upgrade at some point and they are not litronics as no washers. will report back after the bulb assembly swap! also sounds like H7R may be the way to go as my 2004 will have the reflector lenses. Thanks again.

Funnily mine hasn`t got Litronics but has got headlight washers. * * Del.

Yup defo a HID upgrade. It may well be more economic to buy a whole new HID kit of the latest spec... a whole HIDS4U kit is only £84, will be easy to fit as the drilling of the bulb cover etc has already been done and its literally 'plug and play'. https://www.hids4u.co.uk/hidkits.php?car=22355 The ballast will probably be hidden in the front wing behind the light unit... it will be a little box, probably with a shock warning symbol on. Their instructions are very good- fitted a set to my X5 and I was back of the queue when DIY skills were handed out... Are the rest of the functions on that light unit working OK?... just to rule out that it is seating correctly in the connector.

I used slim Ballasts on mine and they will actually fit inside the headlight. * * Del.

Or.. ask your indy to remove the after-market kit and put halogen H7 bulbs back in as your car *may* fail the new 2018 spec MoT with an after-market HID kit. just an opinion.

Stupid MOT rules, obviously much safer to drive around in a high performance car lit by something equivalent to a mildly aroused glow-worm. Why can't the MOT simply check that the light is not scattering unduly such that it would bother other road users (which it does not in projector lights)?

Hi all, thanks for the continued help. yes all other light functions as working fine so connector not an issue (I think). was not aware that the HID kit could fail the MOT, will test that out later this month with my 'friendly' local MOT centre! once I swap the bulb assembly's over tonight and see where we are i'll report back. is the consensus that if I stick with the HID that replacing both at the same time makes sense or will that be overkill? cheers, giles.

the HID upgrade also explain maybe why I get crap radio reception when the headlight dipped beam is on as presumably they must interfere with the reception from alittle reading.....