Defender LED headlight issues

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Mike110

Member
Posts
13
Location
Lancashire
Recently bought a defender 110 300tdi and love it (for now).
Bit of a change from a ford focus.

Background:
As the colder weather set in she struggled to start. Checked the battery and it was only a small little thing. I changed it for a 920 CCA big thing. Started a little better.

Moved on to the cosmetics. Replaced headlights for full LED units (you either love them or hate them). I have noticed that when I only have the headlights on I get close to 14v but when I switch the heater blower and/or wipers on it drops to 13.2ish and the headlights flicker. The car has also been poor on starting in the cold weather again. The issue must of always been there its just the sensitive LEDs have highlighted it.

Measures taken so far:
I have cleaned the earth from the battery - chassis - gearbox.

I am suspecting it may just be an alternator fault?
What would you next steps be to iron this out. I don't fancy getting stuck in the snow (when it arrives).
 
Last edited:
Check the other earth strap as well from the alternator/PAS pump bracket to chassis part of left engine mount. I nicked these pics from another site for my use when I had similar issues!



 
If you have a multimetre you can very easily check the alternator. With the engine off measure the voltage across the battery, should be 12.7V ish. Then start the engine and recheck the voltage, should now be 13.5-14.5V. This will tell you crudely if the alternator is charging or not.

For the price of new ones (even off the shelf at halford) I would agre with @mojo247 not mess around cleaning and instead just replace the earth straps and clean up the areas of the chassis etc the attach to. If there is high resistance somewhere between the alternator and the battery or the battery and starter it will not recharge properly and struggle to start.
 
dag019 said:
If you have a multimetre you can very easily check the alternator. With the engine off measure the voltage across the battery, should be 12.7V ish. Then start the engine and recheck the voltage, should now be 13.5-14.5V. This will tell you crudely if the alternator is charging or not.

For the price of new ones (even off the shelf at halford) I would agre with @mojo247 not mess around cleaning and instead just replace the earth straps and clean up the areas of the chassis etc the attach to. If there is high resistance somewhere between the alternator and the battery or the battery and starter it will not recharge properly and struggle to start.
Click to expand...

Thanks Dag019 your quite right, I will get some bought and fitted. Good to know this is about as complicated as it gets for defender electrics!
 
Mike110 said:
Recently bought a defender 110 300tdi and love it (for now).
....... Replaced headlights for full LED units (you either love them or hate them). I have noticed that when I only have the headlights on I get close to 14v but when I switch the heater blower and/or wipers on it drops to 13.2ish and the headlights flicker. ....
Click to expand...

What LED headlights have you fitted?

Where are you measuring this voltage?

On a 300 TDi there is likely to be dim dip fitted. As voltage at battery drops the voltage out of the dim dip will drop and fluctuate as heater load fluctuates. If this is close to minimum voltage for headlight they will flash.

Brendan
 
leeds said:
What LED headlights have you fitted?

Where are you measuring this voltage?

On a 300 TDi there is likely to be dim dip fitted. As voltage at battery drops the voltage out of the dim dip will drop and fluctuate as heater load fluctuates. If this is close to minimum voltage for headlight they will flash.

Brendan
Click to expand...

They are similar to these:
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/173460109554

I thought 300tdi didn’t have dim dip?
If so is there a way to remedy this? Get a new specialised harness?

The voltage is currently measured off a digital display wired from the cigarette ignition live (so I know it can have a slight voltage loss) I need to unbolt the seat and measure from the battery.

I don’t fancy changing the earths if that’s not the issue. But it’s looking like it’s a process of elimination.

Just strange how the battery was struggling to turn over the car prior to the headlights being fitted.?
 
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Those headlights are not road legal in the UK as they are not approved for road use. Unbranded illegal headlights so where is quality controlled

They claim 75 watts per light. The fuses on a 300 TDi 110 are 7.5 amps so if that power rating is anywhere near correct you are getting close to blowing that fuse.

Dim dip system was fitted to 300 TDi and some TD5.

Need to measure voltage at H4 connector with and without heater blower on.

LED headlights either work if minimum voltage is exceeded or not work if voltage drops below a certain value. That voltage is typically around the 9 volt mark however that voltage can vary between manufacturers.

Brendan
 
Cheers for the reply.

I will check. But I'm sure mine were sold as uk road legal. That was just an example.

Tomorrow I will do all the necessary checks as mentioned here and potentially add new earth straps for what they cost. I may even remove the LEDs as well. Hopefully it will solve the issue and aid the charging and starting of the car. Failing all that it may be the alt. Guess we will see tomorrow.
 
Many sellers state that the LED headlights they are selling are road legal, are E marked will pass a UK MOT etc.



There is a very simple check to tell if an LED headlight is road legal have a look at the markings.

IF the markings on the headlights are DOT, SAE, E + number in a circle then they are illegal.

What is required by UK law is an approval mark. If you want to see what approval marks look like have a look at p28 here


Brendan
 
Right chaps got a multi meter and I get the following.

Battery 12.8 battery clamps the same.
Alternator no lights or heater 14.2
Alternator with lights and heater 14v

Does that suggest the alternator is on its way out and was trickle charging the battery? as it should be kicking out more than that shouldn't it?
 
Mike110 said:
Right chaps got a multi meter and I get the following.

Battery 12.8 battery clamps the same.
Alternator no lights or heater 14.2
Alternator with lights and heater 14v

Does that suggest the alternator is on its way out and was trickle charging the battery? as it should be kicking out more than that shouldn't it?
Click to expand...

That's still a good voltage under load at 14V, do not get a new alternator, the current should be OK.
Your first post said you were getting 13.2V under load (not good), in the post above you said 14V which is OK.

Put the lights to high, the blower/heater on or AC if you have, wipers and anything else to add load to the battery and then measure the voltage, if its close to or around 14 the alternator is OK.
You can also have the alternator tested before buying a new one.
 
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Fair one. Il do that above and double check.
The latest readings are most accurate as the other readings where based off a cheap digital display with a feed from the cigarette lighter.

If it drops below 14v with everything on then it would be an alternator fault ?

I hate electrics. Give me nuts and bolts any day.
 
Last edited:
Mike110 said:
Fair one. Il do that above and double check.
The latest readings are most accurate as the other readings where based off a cheap digital display with a feed from the cigarette lighter.
Click to expand...

Not a good test point because you will have a voltage drop though the cigarette lighter has bigger gauge wires. To be accurate, voltage must be measured on the battery terminals first and then look for voltage drops elsewhere if the test was OK.

Mike110 said:
If it drops below 14v with everything on then it would be an alternator fault ?
Click to expand...
Typically when the battery is heavily loaded, any voltage between 13.2 to 13.7 is acceptable, especially if you are using the Defenders 65 AMP alternator. Remember your battery's voltage is 12V

Mike110 said:
I hate electrics. Give me nuts and bolts any day.
Click to expand...

I love them both and electronics as well LOL

There are thousands of videos on you tube, some are misleading but if you look at a few you will still grasp a lot and learn a lot, look up some on testing alternators with a digital volt meter etc. Dont be hateful or scared of electrics, try to learn a bit of it and you will see how easy the basics are.

Cheers.
 
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