LED Full Beam - Very weird situation

I had meant to post this last week when I had this situation.

I have LED headlights fitted to my 1991 90.

The issue I had (may still have) is that the drivers side full beam didn’t come on when the stalk is pushed in, and the drivers light actually went dimmer.

Also, on flashing (pulling stalk back) I only got flash on one side.

Before I took the lights out, wiring etc I checked fuses - all good. Same issue.

I then started the engine for a moment and the problem just went away.

This makes no sense and I’d rather know why it was like this rather than just have something sit here which could well break again

Thoughts?

Voltage.

My thoughts are ... get rid of the LED's and go back to normal, incandescent bulbs that the vehicle was designed to work with.
This forum is 'full' of LED bulb problems ....

miktdish said:

My thoughts are ... get rid of the LED's and go back to normal, incandescent bulbs that the vehicle was designed to work with.
This forum is 'full' of LED bulb problems ....

Click to expand...

Definitely an option

Earths… remove the plastic wheel arches & put extra earths on the loom behind there .

Similar to Phil's comment -

If your connectors have long prior melted off and you are dealing with spade connectors only, be sure they are all in the right place.

Mine got mixed up once and exhibited similar.

Of course, swap the lights over too, just to make sure the fault doesn't follow the LED.

LEDs are a nightmare especially on older vehicles. They will pick out any corrosion or bad connectors etc and simply not work, where a regular bulb/s with the extra current draw will just carry on like a bull in a china shop
Check. Every. Single. Connection. and you might get somewhere.. on older vehicles you could well have corrosion down inside the wires that you can't see that will act like a resistor

miktdish said:

My thoughts are ... get rid of the LED's and go back to normal, incandescent bulbs that the vehicle was designed to work with.
This forum is 'full' of LED bulb problems ....

Click to expand...

If you are wedded to LED you need to spend real money to get good quality ones. The cheap units themselves seem to be full of reliability issues.
Even once you have good quality reliable LED light units you then have the issues pointed out above by @kermit_rr and @Hicap phill they are far more sensitive to the rest of the circuit than an incandescent bulb so everything else needs to be in fine fetle.

You say they work ok with the engine running so maybe your battery is on it's way out.

In typical forum fashion, I'll admit to skipping the information where it was stated that the lights worked with the engine running.

Most of my prior answer is nonsense then.

The issue, therefore, is poor connectivity causing voltage drop. Anywhere from the fuse box, to the wiper stalk, to any other connections (the dip dim stuff, if it was ever there, even if it's been removed, will have connections) to (most likely) the connection on the back of the bulb which will have gotten roasted by the incandescent bulbs.


My suspicion is that it's not the battery. It may be, but I feel that any battery that's tough enough to spin over and engine is plenty tough enough to run some properly connected led bulbs. At least that what I think...

julianf said:

In typical forum fashion, I'll admit to skipping the information where it was stated that the lights worked with the engine running.

Most of my prior answer is nonsense then.

The issue, therefore, is poor connectivity causing voltage drop. Anywhere from the fuse box, to the wiper stalk, to any other connections (the dip dim stuff, if it was ever there, even if it's been removed, will have connections) to (most likely) the connection on the back of the bulb which will have gotten roasted by the incandescent bulbs.


My suspicion is that it's not the battery. It may be, but I feel that any battery that's tough enough to spin over and engine is plenty tough enough to run some properly connected led bulbs. At least that what I think...

Click to expand...

“Owning up” is a 7 day ban @julianf

Light stalk, indicator stalk are both brand new (washer stalk is not, but I had assumed this was totally unrelated to lighting).

Fuse box is very ropey - glass fuses, spliced wires etc

Wiring on the light is also a mishmash of wago connectors from previous owner

Could well be “all of the above” from your recommendations but I appreciate it

s8ndst0rm said:

“Owning up” is a 7 day ban @julianf

Light stalk, indicator stalk are both brand new (washer stalk is not, but I had assumed this was totally unrelated to lighting).

Fuse box is very ropey - glass fuses, spliced wires etc

Wiring on the light is also a mishmash of wago connectors from previous owner

Could well be “all of the above” from your recommendations but I appreciate it

Click to expand...

If you just want to get it sorted with a relatively low amount of bother, you can get the equivalent of those "boomslang" looms off eBay for about a tenner delivered.

You could just grab one of them and use the current wiring to switch some local relays to run the lights.

Seems like madness for an led setup, but, if you just want to get it sorted "yesterday" that may be your easiest option.

Eg


(I've not purchased that one, know nothing about it, etc etc but it shows what's possible for a tenner, ish)

kermit_rr said:

LEDs are a nightmare especially on older vehicles. They will pick out any corrosion or bad connectors etc and simply not work, where a regular bulb/s with the extra current draw will just carry on like a bull in a china shop
Check. Every. Single. Connection. and you might get somewhere.. on older vehicles you could well have corrosion down inside the wires that you can't see that will act like a resistor

Click to expand...

The dreaded green creep ...

We had some on stored panel repair wire from stores, scrapped loads of it ...

julianf said:

My suspicion is that it's not the battery. It may be, but I feel that any battery that's tough enough to spin over and engine is plenty tough enough to run some properly connected led bulbs. At least that what I think...

Click to expand...

My thinking is that the engine will turn over with low battery voltage i.e 12 volts but the LEDs may require slightly more to fire up.
My TD5 Disco would fire up no problem with low volts but it wouldn't rev as the ECU didn't like it.
Worth checking the voltage at the battery and at the bulb IMO at least to rule it out.

A quick quide to LEDs.

An LED is a semiconductor that emits light
It comprises of two types of semiconductor a P-type semiconductor (larger hole concentration) and an N-type semiconductor (larger electron concentration). Applying a sufficient forward voltage will cause the electrons and holes to recombine at the P-N junction, releasing energy in the form of light.


Pretty much all 12V LEDs will operate when they are given between 10 to 20V, below 10 and they will not energise/emit light.
Above the rated voltage will damage the semiconductor.

So to light up they need a potential difference between Pos and Neg capable of providing the required current (amps) and to be above 10V and below 20V DC.
To get this potential difference you must have a good supply (Positive) and a good (low resistance) earth/connection back to the Neg terminal of the battery.

This means the wiring has to be good to the lamp, any dodgy connections or switches, corroded terminals or wires will reduce the voltage to the lamp. It has to be good back to the battery too. Connecting to the wing will only work if that has a good connection back to the chassis and then via the earth strap on the transfer case to the batteries Neg terminal.

With an incandescant/standard bulb you probably wouldn't see the difference between 9V and 12V or if the earth had a higher resistance than the supply, but with an LED you're buggered.
The more expensive LEDs with have better driver circuits and wider operating voltages, they will tolerate voltage ripple better but overall they are nowhere near as forgiving as standard bulbs.

There is an abundance of current available from a standard landrover so fitting LEDs to reduce current consumption isn't a requirement. The law dictates how much 'light' we can emit so being 'brighter' isn't a reason either. From what I can see it's all about vanity there is no advantage at all (that I can determine).

I can see the advantage of fitting LED flood/spot lamps for offroad use etc (I have a lightbar and two work lamps on the back) but not headlamps etc.

For typical LEDs then yes I agree but the LED voltage regulator may be set higher than 10v. I'm no expert on car LEDs but they may have a cut off voltage to stop battery drain with the ignition off. A quick google of a LED bulb gave Supported Voltage: DC12-17V.

I had a similar issue. After a day of chasing all of wiring through the car... It turned out to be a bad earth to the instrument panel..