www.jec.org.uk

I've been aware that in bright sunlight mynrear indicators are less than bright. Have cleaned them many times but in truth no great improvement. I did buy (couple of years ago now) a brighter set of leds but never fitted them. package says, "off road use only" and might throw a "lighting fault". Anyone else in the same boat?
Nick

I'd guess the "off road" bit is because under EU law you are not allowed to use anything but the originally fitted bulbs 'cos that's what was approved then. If they're the same level of illumination they ought to be perfectly usable, but a copper, and MOT station or very nit-picky insurers might disagree. But as you bought them to be brighter that's going to be an issue anyway.

However, the lighting fault is more likely to be a problem. The XJS has a bulb-failure detection module, and it looks like your bulbs take the much lower LED current which may well trigger it. You should be able to find ones with a ballast resistor fitted to avoid this issue - but then the only advantage of the LED's is supposedly longer life.

I'm astounded by the fact that the rear lamps on my facelift XJS have black "reflectors". I presume it's either a cost-saving, or styling to get a darker rear view in daylight. I've wondered about spraying them with silver or white paint to see if it makes them brighter. That's against the rules too.

The other thing to check is to view them from a reasonable driving distance behind your car - the lenses may well concentrate the light better than you realise to make a brighter view from there, rather than when standing just behind.

Good point Paul - I'd not considered the "type approval" aspect. Never had an MOT issue in my 10 years of ownership so will leave it there for now. As you also comment, a black reflector does seem counterintuitive.

Nick

Nick,

I've been in the same dilemma for some years and am rapidly coming to the conclusion that I will fit LED bulbs on the rear of my convertible soon.

Yes, I understand the legal position. But frankly the design of the facelift rear clusters and the gradual deterioration of both bulbs and lenses means that my view on the safety of myself and other road users will outweigh the legality aspect. Over the years, cars behind have gesticulated their unhappiness at my brake lights, rear lights and indicators. So it's time to improve things.

The one issue is the bulb-failure system and whether the lower current draw will trigger it. However, if it does, I'll probably put resistors in the circuits to compensate. Interestingly, I fitted LED bulbs when I did my front side indicator lens change and it didn't cause a problem. I need to look through the wiring diagram and try and understand that bulb failure circuitry better.

Paul

I note SNG Barratt have LED indicators DBC11382UA at £6.30. Ditto stop/tail bulb DBC11383UR at £10.30 You could check with them that they work with the bulb failure circuit - I've always found them both helpful and knowledgeable. I might even get some myself when I get the XJS back on the road.

Thanks Paul - I'll give SNG a call in the morning and see what they say.
Nick

Nick/ Paul,

I thought I'd posted this last night but it doesn't seem to be there!

Following your post Paul, I rang Steve at SNG and asked about the XJS bulb failure issue. He admitted that he didn't know about it, or the impact of these LED bulbs. But he agreed to go away and investigate and let me know.

I'll post back here when he gets back to me.

Cheers

Paul

Thanks Paul - We all await with interest as sure this affects many facelift cars.
Nick

These are advertised as for XJS and from a very good company so should work

https://www.bettercarlighting.co.uk/ind ... ductId=605

https://www.bettercarlighting.co.uk/ind ... ductId=387

cafcpete,

I'll give them a ring also tomorrow. The problem is that I don't see how any of them can work properly in conjunction with the bulb failure warning module on late XJSs as the LEDS draw so much less current?

It'll be interesting to hear their answer.

Paul

It will be interesting to hear what he says!

I'm also waiting. I've got such a big box of bits that I have acquired these last few months with good intent of installing. Did actually get round to doing the oil light sensor and the crows foot spanner came in really handy (at least the light no extinguishes). Also replaced the micro switch on the handbrake (at least the handbrake warning light goes out). Usually a judicious bending of the contact does the job but sadly not this time. Changed over the cam cover seal, plug seals and isolator rubbers. All four wheels refurbed.
Happy days
Nick

Nick,

You've been a busy lad haven't you?!


OK, I had a great call with Gil Keane from www.bettercarlighting.co.uk the other day. A really knowledgeable and helpful guy with first-hand experience of owning XJSs amongst other classic cars. He's hugely helped my understanding about the issues we face and the potential solutions.

As late XJS owners, we have 2 issues:

- A bulb failure warning system that operates in a particular manner which give challenges to a move to LED bulb technology

- An indicator circuit which has its own challenges for replacement to LED bulbs


The good news is that the bulb failure module only monitors the light circuits, not the indicators. The other issue is that it looks for minimum current draw and continuity. So, for example, if you put extra bulbs into the circuit, it doesn't mind the extra current draw.

So, when the sidelight and stoplight bulbs are replaced with LEDs, the reduced current draw from these more efficient bulbs would cause the bulb failure to illuminate. Gil has developed an answer with a combined resistor / diode in the circuit to signal to the bulb failure that all is well. Whilst therefore losing some of the potential benefit of reduced current draw from the battery, it seems a small price to pay for the better illumination, quicker trigger time and longer life that the bulbs can give. Below is the kit available from Better Car Lighting. The bulbs etc can be bought separately.
The indicator circuits don't go through the bulb failure circuits, so we don't have a problem there. (This also clarifies why the replacement of my front wing indicator bulbs with LEDs didn't cause me an issue.) However, the indicator relay demands a minimum of 40w to operate which is in excess of the load of a set of indicator LEDs. Gil therefore has a developed a replacement relay that operates from .1w to 100w to handle any combination of bulbs within that circuit. The electronic relay has also got a built in sound circuit to deliver the expected clicking sound. Again, the pic below shows a kit from Better Car Lighting. As before, the components are available separately.


So, it seems we have some answers and purchase options whether from this company or elsewhere. Certainly I have clarified my own thinking. I intend to start by fitting the stop / tail light kit from Gil in the next few weeks and will publish an article showing the work involved and the results. I'll then change the rest of my indicators.

The last thing I would mention is that there are huge differences in the price and quality of LED bulbs that are available. You can buy very cheap simple ones, but if you're going to change your bulbs, I'd suggest that you really need to be buying the high-power multi-cob variety.



And then of course, we come to the almost invisible dashboard warning lights for late XJSs and the use of LEDs to improve those! But that's one for a different thread!

Hope that helps Guys!

Paul

Thanks Paul - I will be following this one closely.
I once found myself in the strange position of following my own car and that made me realise how dim the tail lights are compared to modern day ones.
I'm looking forward to publishing the article!

Hi Paul

All makes extremely good sense to me. The only bits left that still have me wondering is the "Type Approval", "MOT" and the Law element. Interesting insurance issue as well since the dimmer bulbs potentially pose visibility issues (especially in sunlight). Just wondering if there is a combined case for making the point, that in some cases "Safety" of others and ones self top-trump original equipment requirements. Perhaps just opening a bag of worms.

Nick