Unusual lighting system

[928jr]

I've got an unusual wiring set up at the front of my engine bay that seems to lead off to both the headlights. I've never seen the electrical system for the headlights positioned in this way before, has anyone else? If you have, do you know why it's been changed?




Cheers,

[DougM]

Aftermarket HID?

[MPDano]

Originally Posted by DougM

Aftermarket HID?

I agree. Pop the Covers off and take a look at the Bulb behind the Lense.

[palaur]

it's usually done because to a low voltage on the headlight,( if you have low voltage, you can use the original cable to use as a control to the relay and then you u need only one new + cable and get 12 volts directly on the headlight without losing volts through the original light switch, fuses, and so ..

[Alan in AZ]

Probably just local headlight relays - a good idea for brighter lights and less CE panel loading - However this is an ugly implementation...

Functionally may be fine - but why put it all there.....

Alan

[Danglerb]

I would follow the wires and see what it takes to remove the mess and fix it correctly.

[Pete R]

Originally Posted by Danglerb

I would follow the wires and see what it takes to remove the mess and fix it correctly.

I half agree.. fix the mess, don't remove. I'm assuming it's an HID light set up. Which is very bright and much better than the stock lights. If all that stuff was hidden it would be nice, but even if you can't I wouldn't go back to the stock lights just for that reason

[Alan in AZ]

Originally Posted by Pete R

I half agree.. fix the mess, don't remove. I'm assuming it's an HID light set up. Which is very bright and much better than the stock lights. If all that stuff was hidden it would be nice, but even if you can't I wouldn't go back to the stock lights just for that reason

I already told you what it is - this is not HID - or if it relates to HID it is done to reduce voltage drop for the HID units which are elsewhere - these are LOCAL HEADLIGHT RELAYS. They should really be in the fenders or in the headlight buckets.

IMO HID installations in 928 headlight lenses are usually quite awful and will likely blind those driving towards you... good idea?

I'd not call that 'much better than the stock lights' - if you want better lighting buy genuine Bosch H4 headlamps - what the car was designed to have - and does have in the rest of the world.

Now the local headlight relays perform a useful function with stock lights (which I suspect is what we have here) - much more light output - maybe close to twice as much. again this works much much better in H4 lenses than in any DOT configuration (sealed beams or H5's)

Alan

[bluemane500]

easy does it Alan opions are always welcome

[Alan in AZ]

Since the OP wants to know what he actually has, and should do - its useful to have something other than multiple different opinions on what it is. Really - put yourself in his place...what is he asking?

It clearly isn't a HID system - anyone who has seen a HID system could tell you that.

And yes I do have an aftermarket HID system, and have installed many different ones - and yes I do have a local headlight relay system - it doesn't look at all like this - though I recognize the component parts.

My local relays are installed inside the headlight buckets with seperate relays per side and fuses for each filament which I recommend as an implementation strategy.

Of course we can pretend that its a HID system if we want to confuse the OP - but I thought the point of technical forum was to solve peoples problems as quickly as possible.

IMO off topic is the better place for just throwing out differing opinions and debating them.

Maybe I'm just being cranky today

Alan

[wallstreet]

Originally Posted by Alan in AZ

Maybe I'm just being cranky today

Alan

Cranky ... no.. maybe realistic.
I thought the purpose of the relay was to switch power direct from the battery using the relay controlled by the OEM dash switch.
One thing i would like to have the OP answer is 'what type of lamp /bulb is installed.
It appears to be a Bosch H4 type lens.
Alan, doesn't HID use a specific bulb?
G-Man

[Alan in AZ]

Yes these lamps look like H4s which would be a PO upgrade on a USA car. These could have HID's in them - but I hope not - they certainly don't need them - Bosch H4's with uprated bulbs and local realays is the configuration I recommend most - its hard to beat this configuration.

In a typical local relay system on a 928 you use the stock switch & headlight relay to power the coils of relays near the headlamps (which is why the buckets are best) using large gauge wiring (~12 AWG) to reduce voltage drops. Voltage drops at the bulbs can be as much as 2v on uprated bulbs - this causes massive luminous output loss - this is not even close to a linear relationship (~proportional to V^3.4). Local relays will also prolong the life of your headlight relay and allow much brighter bulb use (but don't uprate on H5's see below). Ideally seperate relays per side (2 each side), ideally a fuse for every filament (the stock fuses on CE no longer protect you) and a master fuse each side to protect the power feeder that must run up through the articulating headlight carrier.

Duplication of relays is so they can be truly 'local' - and so you never lose more than one side of lighting for any given fault. If you have ever been driving at night and lost both headlamps you will understand the critical importance of this...

HID can use different format capsules & bases matched to exisiting incandescents - so H5 or H4 types are available. However they work differently optically since the discharge arc is very small vs the linear filaments in incandescents.

Usually types that replace dual filament high/low beam bulbs (like H5 & H4) feature a movable (tiltable) capsule or a moving shield to expose the bulb for high beam.

The problem with this is that real dual filament bulbs have two filaments in different fixed places - these cannot be replicated by these methods so often the beams are far from ideally focussed. You hope that the arc is actually centered exactly where the low beam filament should be beacuse if not (and its rarely exact) the more critical (at least in H4's) low beam focus will be off. In H5's the focus pattern is already poor to begin with.

This is further compromised by the afore mentioned wrong shape of the arc vs filament. H5 (9004) bulbs have transverse ~ 1/4" filaments while arcs are almost always axial and short in length. Since HID arcs are very bright in the center and filaments are bright uniformly along their length this creates significant optical issues in an already poorly focussed lens system, however H5 low and high beam filaments are at least closely placed - offset side by side at ~ the same point on the axis. This means the high beam can be a resonable focus.

H4 (9003) bulbs have axial filaments which rather better match the axial but shorter arcs. However the high beam filament on an H4 is mounted a significant distance down the axis from the low beam filament meaning bigger difficulties for high beam focus, so neither bulb type is ideal for HID replacement

However given that low beam performance is much more important, H4's are preferable and their good optics for low beam mean you will still get a quite crisp vertical cut off that avoids the extra HID brightness being a major problem for others. However the high beam focus will be very poor.

H5s have such a significant spill pattern on low beam that HIDs much higher output (~ 5x) and even poorer focus means the headlight will be unusable from a practical safety perspective - in other words no matter how you adjust them you will be blinding other motorists (so dont do it).

Alan

Oh and BTW since I said I have a HID system - mine is in my Fog lamps - used for supplemental lighting, fog and DRL - even there modifications are required to the lens system for this to be safe for others.

[Alan in AZ]

ye gods....

[19psi]

Either drunk or trolling.

[Alan in AZ]

Ye Gods again!!

Eddie - engage brain...

[928jr]

Thanks again guys for your help, esp. Alan for the 6 posts!! I've been on holidays for a week and so I'm stoked at all the replies! To tell you the truth, I don't fully understand what's been said and what I have to do to fix it, but give me a few hours tomorrow morning and I recon I'll have a much better idea of it all.

I've spent most of today removing 2 separate alarm systems from the car, one a gps locator/immobilizer the other a standard ignition kill switch. these were not only getting in the way but must have been dragging on the electrics, something my car can do without.

Unfortunately a weird wiring set up isn't the only lighting issue. In the lower set of lights my halogens are on the inside and the lenses are marked with HR Halogen, the outer lights are standard bulbs and the lenses are marked with B. I have to replace the outer one that has been stone damaged, so I ordered a right driving light lense from 928intl (928 631 414 00). 928intl sent me a HR Halogen lens, are the outside lenses fog lights?.

I might just add that when I press the front fog lamp button nothing happens, and the other lower driving light bulbs inc the halogens that are also blown or not working (the previous owner had never really driven in the dark so didn't bother replacing any bulbs but the essential indicators,headlamps and brake lights) The dash lights, most interior lights, under bonnet light don't work either, I'll be getting new ones asap though. Other things that I need to fix are the headlights only rising 80% of the way, it needs manual adjustment by winding the screw at the front to direct the beam onto the road and not into peoples rear view mirrors!

[928jr]

Hi Guys,

I've finally started to make some serious progress on this car this week, almost all electrical items on this car are now WORKING!! Headlights go all the way up now too. Every globe except for the the under bonnet one function now. In the past few months I've done the water pump, timing belt, alternator, washer hoses, brake hoses and gearbox to name a few!

I thought some of you may be interested to hear how I went with the lighting.
I think I now know why that crazy wiring set up near the bonnet release was installed, it seems the original fuse connections on the board blew out completely (see 'dipped beam' port 26 & 27 of photo). From what I can tell, they have then re routed the lighting through the 'main beam' (I'm guessing that means H.B.) to ensure all lights still work.
I think this may explain why my high beam dash light comes on as soon as I turn the lights on, even if they are still on low beam. I'll look into this bit further anyway.

On another note I'm after an original radio for my car, I could put a CD player in but I'd really like the car to look completely retro and period.. i'm 21 so a tape player is a real novelty item for me!

Cheers

P.S. This photo was taken before I changed all the fuses back to the correct ones.

[Danglerb]

"Under bonnet" I think only comes on when "parking" lights are on?

[928jr]

Ah that explains it, Ive been looking everywhere for a switch, unfortunately mine doesn't work even when the parking lights are on though, i'll get onto that. Not that it's a major issue, and it doesn't look all that well placed anyway, but it would be nice to have everything working.

On another topic, do you know how to set up alerts for when you recieve a new post? I keep forgetting to check if anyone has replied.

Cheers

[MPDano]

Once you click on the Advance reply, you'll see this box at the bottom.