Problem with new LED headlights

Hi. We have a defender td5 (with dim dip relay) and have tried to install some new LED headlights.

We have removed the fuse for the dim dip (and have removed the pink relay behind the dash and bridged the connectors). Our new LED headlights work for a while, but they cut our either (1) when I have been driving for a while and/or (2) when I operate full beam and turn it off again (although not every time!). When the dipped beam is no longer working, I can still operate full beam. The side lights stay working throughout. All the fuses are intact. We have recently changed the light switch and the indicator switch.

The input current for the dipped and the high beam is listed at 1.5A at 12V on the new LED lights.

Any suggestions for what to explore would be gratefully received!

Don

well its going to be more than 1.5 amps I assure you. Otherwise you have 18w of headlight...

I know this might sound stupid, and I will research it, but isn't 18w high for an led? I know absolutely nothing about led lighting (yet) other than I just replaced my standard kitchen bulbs with 4w led ones and they're brighter than the old halogen thingys.

Discokids said:

I know this might sound stupid, and I will research it, but isn't 18w high for an led? I know absolutely nothing about led lighting (yet) other than I just replaced my standard kitchen bulbs with 4w led ones and they're brighter than the old halogen thingys.

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No.
The original post doesn't state the make of headlight but my Nolden LED's (for instance) are 32W(Low) & 39W (High).

Remember that a headlight throws out considerably more light than your average domestic light.

My LED headlights are 35watts, per beam so 70 watts when you combine them. That's each side.

Thanks for clearing that up, come to think of it, there's 8 of them in my kitchen and they probably don't shine that far either. I'll shut up now.

Sounds like a wiring fault. When it doesn't work, trying flashing the stalk switch and see if that makes a difference. And check your connections, obviously. The drop in current draw may be showing up a poor connection somewhere.

They both go out? Switch fault or something.

Do they come with a remote driver or is it all integral?

Discokids said:

I know this might sound stupid, and I will research it, but isn't 18w high for an led? I know absolutely nothing about led lighting (yet) other than I just replaced my standard kitchen bulbs with 4w led ones and they're brighter than the old halogen thingys.

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Talking in watts for LED's is like talking in apples to measure pears.

Wattage as a measurement of light will be a thing of the past within the next decade.

A standard (GE made for this discussion) H4 lamp is 1000/1650lumens (dip/high).

LED lamp efficacy is easily 100lumens per watt and heading fast toward 200 lumens a watt. I can get an 23W LED 3000lumen downlighter, that's an efficacy of 130lumens per watt.

So in LED terms, a recent 18W could be a good 1800lumem LED so more than enough for a headlight in high beam mode - also bear in mind an LED light is all focused forward so there is less wastage like an indiscriminate source like a halogen lamp.

zeaphod said:

Sounds like a wiring fault. When it doesn't work, trying flashing the stalk switch and see if that makes a difference. And check your connections, obviously. The drop in current draw may be showing up a poor connection somewhere.

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Hi.
Thanks for your reply - that's really helpful.
Re: flashing the stalk: When I start up and turn on the lights everything is usually OK, but after I have been running a while the dipped beam can go off. If I flash the indicator stalk the full beam comes on but doesn't necessarily mean the dipped beam comes back on. At other times I can be running with the dipped beam on and after I pull the indicator stalk to flash the full beam, the dipped beam stops working. Sometimes, repeated flashing of the full beam and turning the dipped beam switch on and off can restore function, but not always.
I will double check the connections and spray some contact cleaner on. The light switch and the indicator stalk are both new, so I will check whether the connections were firmly seated when they were replaced.
Don

discomania said:

They both go out? Switch fault or something.

Do they come with a remote driver or is it all integral?

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Hi
Thanks for the reply.
Just the dipped beam stops working. The full beam works OK whatever happens.
The units are integral (i.e. no external modules, switches, relays, etc). We bought the lights from a stand at the LRO show a few weeks ago. Unbranded make but claims to have the E-mark certification.
Don

discomania said:

Talking in watts for LED's is like talking in apples to measure pears.

Wattage as a measurement of light will be a thing of the past within the next decade.

A standard (GE made for this discussion) H4 lamp is 1000/1650lumens (dip/high).

LED lamp efficacy is easily 100lumens per watt and heading fast toward 200 lumens a watt. I can get an 23W LED 3000lumen downlighter, that's an efficacy of 130lumens per watt.

So in LED terms, a recent 18W could be a good 1800lumem LED so more than enough for a headlight in high beam mode - also bear in mind an LED light is all focused forward so there is less wastage like an indiscriminate source like a halogen lamp.

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Hi
Thanks for the reply. The unit claims 1000 lumen for low beam and 1000 lumen for high beam. It is certainly nice and bright on the road (when working reliably).

To prove the units, you could run a temporary 12v lead from the battery to the dipped beam feed. I'd connect it into the loom under the bonnet. Then try the lights/flashing high beam etc. If it stays on, the problem is probably in the stalk switch.

Just one further thought, before you go to too much bother - check the dip beam fuse is nice and tight.

zeaphod said:

To prove the units, you could run a temporary 12v lead from the battery to the dipped beam feed. I'd connect it into the loom under the bonnet. Then try the lights/flashing high beam etc. If it stays on, the problem is probably in the stalk switch.

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Thanks Zeaphod. The fuses are all snug, so I will try your suggestions about the direct feed.

I had the same fault it really has been infuriating trying to trace the fault. AA for 2 hours they said fit new light switch and dim dip relay it made no difference, the lights would cut out after 30 mins or so.

I had a look at the yellow relays below the main fuse box near the gear leaver, I found one had a burnt/corroded terminal. I cleaned it up best I could and refitted.

Fingers crossed that's cured it, I've been driving around all weekend with the headlights on and their still working!!!!

I changed to LED headlights a few months later because of the lower draw(that's my excuse anyway!), 18 months on I've never had the problem reoccur.

Double check the fuse, I had an issue a while back and the fuse was intact and appeared to be fitted correctly, but one of the fuse spades had pushed the female terminal out of the back of the fusebox, causing an intermittent connection, there a little tag on the female that can be bent a bit to secure it again in the block....

Paul

chilipepper said:

I had the same fault it really has been infuriating trying to trace the fault. AA for 2 hours they said fit new light switch and dim dip relay it made no difference, the lights would cut out after 30 mins or so.

I had a look at the yellow relays below the main fuse box near the gear leaver, I found one had a burnt/corroded terminal. I cleaned it up best I could and refitted.

Fingers crossed that's cured it, I've been driving around all weekend with the headlights on and their still working!!!!

I changed to LED headlights a few months later because of the lower draw(that's my excuse anyway!), 18 months on I've never had the problem reoccur.

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Thanks Chilipepper
An intermittent fault is the most infuriating!
We were at our club's annual TYRO yesterday and the club members were puzzled when I explained the problem (so at least it wasn't just me!). A couple of the guys spent some time ferreting under the dash and bonnet with circuit testers and voltmeters, and concluded that it wasn't the LED units themselves, the switch or the connectors into the switch. Their conclusion was that it was upstream of this lot, so places it in the territory of the loom/fuses - which is exactly where you are suggesting I look.
I will look around the fuse box and see what I can spot. Another suggestion was to replace the relevant fuses (even if they look good) since a hairline crack in the fuse could open up when load is put through it and it heats up (I might even go through the precaution of replacing all the fuses with new ones - for the sake of a few quid it would provide peace of mind). I will look around to check the integrity of the wiring etc. Hopefully, a Sunday morning and we will be sorted, but I will keep you posted ...
Don

paulnb said:

Double check the fuse, I had an issue a while back and the fuse was intact and appeared to be fitted correctly, but one of the fuse spades had pushed the female terminal out of the back of the fusebox, causing an intermittent connection, there a little tag on the female that can be bent a bit to secure it again in the block....

Paul

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Thanks Paul. We will give that one a look too.
Don

I may be wrong but I was always under the impression that when fitting LED headlights the standard dim-dip relay needed to be chucked?