Rear LED Lights

[Laird Scooby]

Originally Posted by Stephen Edwin

how does the output of those 5w LED compare to a 10w filament bayonet bulb please?

Stephen

Forgot to answer this bit! ops:

The Lumen (Lm) output of the average 5W filament bulb (sidelight bulb) is about 50 Lm, most LED replacements are in the region of 80-110Lm so a bit brighter.
Not enough to be confused with a different/wrong bulb but brighter.

Moving up the scale, the 21W stop/fog/reverse/indicator bulb is about 350Lm in filament bulb form. The LED versions are generally about 500Lm with the combined stop/tail (as linked to above in the previous post) are about 660Lm , not sure exactly how that is split between the two functions though.

The average 55W halogen bulb (headlamps etc) are between 1200-1600 Lm, depending on the exact mix of gas in them - we've all seen Nightbreakers, they use a specially wound filament and a slightly different mix of halogen gases to make them brighter (but the LED bulbs i linked to outshine and outlast them - proven fact, if i can find the photo i'll post it) so they're probably on the upper end of this, the el-cheapo halogen bulbs you can buy for £2.50 each from places like ECP, GSF etc are lucky to reach 1200Lm when they're new.

Because all filament bulbs rely on the filament getting hot, there is always an element of blackening on bulbs, especially older ones. Again, not with the LED bulbs as they don't get anywhere near as hot.

[Stephen Edwin]

So they are 15mm bayonet. Thank you.

The comparison to 10w filament bulbs would be interesting. Sorry if I missed that one.

It's a shame there doesn't seem to be a way to combine a thread for both sections of the forum. There seems to be a common interest. Some of us could benefit from the knowledgeable people in the two sections combining together to advise.

Anyway do consider looking at and maybe contributing to those 240 section threads.

Stephen

[Laird Scooby]

I've never owned a 240 (although i used one as a pool car quite a lot many moons ago) so i tend not to lurk on that part of the forum. That said i have owned a couple of 140s and a 360 (even owned a 440 LXi for a short while too ) but i never really find my way to those parts of the forum either.

In the main my Volvo ownership has been 3x 740GLE auto estates and my current 760GLE auto V6 estate so that's where the bulk of my knowledge is.

[GrandadRob]

OK got the correct LED's from Class car LED. They fit ok and work, but there are two issues. First the bulb fail light is always on. Secondly the high level brake light has a constant background glow, this does not happen on the old style bulb. Any thoughts please.

[GrandadRob]

Spoke to Duncan who was very helpful. However, he did say that Volvo's have the most sensitive bulb fail style and this causes a problem. He offered me a set of resistors to fool the bulb fail system These would need to be wired into each brake light and the high level one too. In the 965 estate it is a skin stripping job just getting to the bulb, so adding to the wiring in this tight space is too much for me. So, sadly, the bulbs are going back.
He did add that Dave's experience with these led's related to his Rover which is less sensitive.
So if it's Led's you want get the resistors too.
Thanks to all for your help. Rob.

[Laird Scooby]

You don't need the resistors Rob - and you don't need to send the bulbs back either!

I'm almost certain you have a bad earth, probably on the left hand cluster and that is causing the dim glow on the high level brake light - does this glow disappear when the ignition is off?

If so then try pulling fuse 23 (i think it's 23, for the Day Running Lights) and see if the glow remains absent.

If so, check firstly that you have fitted the stop/tail bulbs correctly, the pins are staggered in height and this is mirrored in the holder to ensure correct fitment - somehow it still happens that they get fitted incorrectly.
Assuming the bulbs are fitted the correct way round, check all the connections to the bulb holders, bad earths here are common on Volvos, even with "normal" bulbs. Also check the earth point which if memory serves correctly is below the left hand light cluster (saloon and estate) to ensure it is clean, rust free and tight.

When i say "check" i don't mean just look at it, remove the bolt, bulbholder or whatever and use some fine emery or wire brush as appropriate to clean the earths.

Now re-try after carrying out those checks.

Adding the resistors to provide a dummy load won't help, the brake circuit is tested separately and it is highly likely it is the sidelight circuit that is bringing the bulb failure warning on constantly, the bulb failure only lights when the brakes are applied if it's the brake lights that are causing the fault.

If you have the older 740 with the 21/5W front sidelight/day running light bulbs, speak to Duncan again and ask him for a pair of those in white to match the current draw of the red stop/tail bulbs. This should put the bulb failure warning light out if it is on constantly.

If all else fails, i know Duncan is happy to accept returns but we're not playing with the latest hyper-sensitive bulb failure modules on the Volvo, yours will be 20-30 years old depending on the model.

The Rover doesn't have a bulb failure module so i don't know where Duncan got the idea it did!

[GrandadRob]

Thanks Dave, I would rather keep them, and make them work.
I have the 960 so no bright daylight running lights, just two small ones within the headlight cluster. (should I get some led replacements to balance up the rear ones ?)
I will check out the earth's as you said.
It was a strange outcome. The two bottom led's worked fine, brake and sidelight, but ONLY if I had an old style bulb in the high level one. As soon as I put the led in the high level one, the bottom ones stopped working. The whole time the bulb fail was on....that is constant and not only when the pedal was pushed.
The rear bottom bulb holders are not in an easy place to reach. You remove a large bulb holder by rotating it out. Then replace the bulb, and try to refit it in the correct place. It has shaped lugs, so cannot be replaced wrongly.
Another job for next week, thanks again.

[Laird Scooby]

That's a strange problem you have there Rob! Do you know if it's ever had any work done on the back end, in particular involvoing removal of the light cluster(s)?

Alternatively it could be the high level brake light has been removed and refitted with the wires the wrong way round - i'm guessing yours is an estate so fairly easy to get at the high level bulb?

The thing with LEDs is they only pass current one way so the clue here is that the bottom ones would only work with a normal bulb in which isn't polarised.

On a negative earth car, the outer part of the bayonet fitting is always earth and the contact pins are positive. If you have a multimeter you can confirm this is how the holders are wired and probably get rid of the fault as well.

Also double-check you've got the bulb holders back in the right place and pushed all the way in then turned to secure them. I know from experience how awkward these can be and just how easy it is to misfit them.

As for the front sidelights, LEDs there would be a useful addition but as long as the balance is kept in the sensing circuits then either should be fine. My blub failure warning is almost constantly on as well but that's because mine is old enough to still have dim-dip and i've got LED headlamp bulbs as well as LED sidelight bulbs. Like the 960, mine only has the sidelight bulbs, not separate sidelight/day running light filaments like the early 7xx models but mine are in a separate cluster from the headlamp, same as the other 7xx models although mine is the facelift being a 1988 760.