DEFENDER2.NET - View topic

↓ Advertise on Defender2 ↓

Home · FAQ · New Posts · My Posts · PMs · Search · Members · Map · Calendar · Profile · Donate · Register · Log In

Home > Technical > Interior light

Page 1 of 1

Print this entire topic ·

Gav40

Member Since: 30 May 2015
Location: Maidstone
Posts: 41

Interior light

Interior light not working with door switch.

Bit of history first, was originaly a County station wagon with two lights in headlinning and worked when door opened and had timed delay and would come on with unlock button on key fob and go off when locked with fob. My fob is for alarm attivation only not central locking.

Car was then converted to a pick up and the roof wiring loom was stripped out and lost.

It has now been turned back into a hardtop and refitted with interior light and basic roof loom. The interior light only works with the switch on the lamp and not with either door switches, I know the door switches work as have tested them with voltmeter and the factory alarm will go off when door opened. The red immobiliser light also works with the door switch.

I have a basic nancocm and have set the interior light to 'smart' thinking that this would be the right setting?
It's not a major issue but can't get my head around why it's not working as it once was.
Any help appreciated.

7th Jun 2016 2:51pm

agentmulder

Member Since: 16 Apr 2016
Location: Outer Space
Posts: 1324

On the TDCi the lights have two 'inputs', one is a the 10AS unit alarm unit that also controls the timing and interior light fade, another is straight 12V.

Either the 12V is connected to GND via the bulb in 'ON", or the 10AS is switched to the 12V via the bulb in 'AUTO' (the 10AS acts as a variable GND)

In your case I'd open up the lights and check to see if you have any connectivity in 'auto' - if so, trace that back to it's source... If it's a TD5 I believe they have a 10AS also Solved the bowel problem, working on the consonants...

7th Jun 2016 6:42pm

huffhuff

Member Since: 05 May 2016
Location: Home Counties
Posts: 379

Interior light switch in the middle position?

My nanocom (evolution) has an 'interior light' and 'welcome light' setting TD5 Defender 90
Discovery 3 HSE

7th Jun 2016 7:42pm

Gav40

Member Since: 30 May 2015
Location: Maidstone
Posts: 41

Yes it is a TD5, should have put that. I will try your suggestion of checking to see if there is power in the middle position, thanks.

7th Jun 2016 8:18pm

agentmulder

Member Since: 16 Apr 2016
Location: Outer Space
Posts: 1324

There isn't so much 'power' in the middle position.

12v is the source, you're switching the other side of the bulb, between GND (ON), the 10AS (AUTO) or air (OFF). Solved the bowel problem, working on the consonants...

7th Jun 2016 8:34pm

agentmulder

Member Since: 16 Apr 2016
Location: Outer Space
Posts: 1324

Looked up my old notes, you should have continuity between pin1 on the grey 10AS unit and the AUTO position contact on the interior lights switch (the one that isn't 12V or GND).

Memory is foggy but it may have 12V reading when the lights should be off, and near 0V when the lights should be on (inverse logic probably as it's a sink)

Google '10AS pin out defender' for more info... Solved the bowel problem, working on the consonants...

8th Jun 2016 4:12am

Cupboard

Member Since: 21 Mar 2014
Location: Suffolk
Posts: 2971

2011 Defender 110 Puma 2.4 HT Corris Grey

Yes, that's right.

If the interior light is connected up properly and working, then the 10AS pin for it will be 12V for off (that is no potential difference across the bulb, and the current path through the bulb pulling it up) and 0V for on (that is a 12V potential across the bulb and the resistance to ground through the 10AS being much lower than through the bulb).

When dimming, the two ways of doing it are genuinely creating a variable voltage, so if you have 5V at the 10AS and 12V at the bulb "input" then you've got 7V across the bulb, or the way it's actually done is by turning the bulb on and off very quickly in a process called Pulse Width Modulation or PWM which is much cheaper and easier to do.

The problem you'll have when testing it is what the 10AS pin will do when there's no bulb pulling it up. Because it's not actually a 12V source, it's just a very high resistance sink to 0V, the voltage isn't actually defined as anything in particular. You'll probably find that it will actually work with a much higher voltage than 12V and may well be able to dim a 24V lighting circuit that shares the same earth.

I have my 10AS dimming my lights which aren't actually fed from my starting battery, and have the slightly weird phenomenon that if the car has been sat a while and the main battery is a bit low, when it first turns the engine over the lights briefly flash on. Most cars when you turn the engine over the lights dim if they're on, mine actually turn on if they're supposed to be off. Now if the 10AS was genuinely not providing a 12V supply to the lights to make them off and was just, like I said, providing a high resistance to 0V then I don't think that would happen. If on the other hand the 10AS was actively driving the pin to it's nominal 12V which then drops to something like 9V when cranking, then you'd get a 3V difference between the 12V of my aux battery's supply and the 9V "12V" supply from the cranking battery which triggers the lighting glitch.

8th Jun 2016 9:46am

Gav40

Member Since: 30 May 2015
Location: Maidstone
Posts: 41

Thanks for the above replies, helps me get a better understanding of what's going on.

I have a basic voltmeter only and have little understanding of vechile electrics, both wires have power/ volts going into the light and I have changed blub and lamp unit to rule out faulty ones.

I did have a play around with my nanocom last night and it is set to 'welcome light' and not 'smart' as I originaly put in my first post.

I have manage to get the light to flash in the middle position with the nanocom performing a test function so there can't be to much wrong with the wiring. Think it may be a setting is wrong somewhere.

Thanks anyway

9th Jun 2016 6:23am

huffhuff

Member Since: 05 May 2016
Location: Home Counties
Posts: 379

Just for your reference, I plugged in my nanocom this morning;

Interior light is set to SMART
Welcome light is set to ENABLED

My interior lights come on when I open the door and/or when I PLIP my remote. TD5 Defender 90
Discovery 3 HSE

9th Jun 2016 7:34am

Gav40

Member Since: 30 May 2015
Location: Maidstone
Posts: 41

Ok, thanks I will have another look

9th Jun 2016 12:12pm

Gav40

Member Since: 30 May 2015
Location: Maidstone
Posts: 41

I now have fully functioning interior lights!

I set the interior light as you said on nanocom and then wrote the new settings to the ecu and hey presto all working.

The error I was making was not writing the new settings to the ecu

Many thanks everybody.

9th Jun 2016 4:00pm

Cupboard

Member Since: 21 Mar 2014
Location: Suffolk
Posts: 2971

I like easy fixes where you've worked out what was wrong

Thanks for letting us know.

9th Jun 2016 5:20pm

agentmulder

Member Since: 16 Apr 2016
Location: Outer Space
Posts: 1324

It's funny how those lights are so unappreciated when they're working!

In my case (literally) the 10AS wire for auto was touching GND which forced it to 0V and left the lights on all the time...

As cupboard says, very nice feeling to have actually found the fault.

[/i] Solved the bowel problem, working on the consonants...

9th Jun 2016 7:15pm

Landymatt

Member Since: 31 Dec 2018
Location: York
Posts: 191

Hi folks does anybody know if there is a way to change how long the interior lights stay on? 2015 Puma...
Cheers Matt

9th Jan 2019 9:38pm

Page 1 of 1

All times are GMT

Jump to

< Previous Topic | Next Topic >

Posting Rules

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum