12V lighting circuit advice please

[paul18]

Been fixing another 12V LED light into my van, but power to that particular area just went. Makes me think its a fuse obviously, so checked with multimeter and yes, no current. However the other lights are working, ie, under hob and rear bedroom area lights, just not the front ones. Cant find a fuse thats blown from my fiddling, and manual no help. I am assuming there must be an inline fuse or another fuse box I cant find somewhere? Can anyone help please, its an 04 Ace (Swift I believe)

 

[paul18]

Obviously open circuit between the two.

Sorry I dont undertstand what you mean. The "dead" wires are the orange/white & grey/green. I isolated my new circuit and connected it to a 12v outlet, all work fine. The existing source is "dead" as if a fuse has blown, except there isnt one

Have you tried a continuity test between the individual lights?

Oops just crossed with Jonkil!

All the other lights work fine and havent been touched

 

[Gellyneck]

Sorry I dont undertstand what you mean. The "dead" wires are the orange/white & grey/green. I isolated my new circuit and connected it to a 12v outlet, all work fine. The existing source is "dead" as if a fuse has blown, except there isnt one

All the other lights work fine and havent been touched

Maybe I'm misunderstanding?
Say you have got 3 original lights A - B - C and have added D (to C).
A, B and C work but D doesn't?
Have you ran a continuity test on the wiring after C to D?
Or have I got the wrong end of the stick?

 

[paul18]

I`m not sure from the wiring diagram which light comes before the one i used as a power source, but all the others work. I previously added two LED lights with no problem, its since I tried adding a 3rd that the power has gone to the light from which I accessed the power. Its hard to explain. But I added to ABC - D&E and all was well, since I added F only A & B work. If I put 12v to C it works fine as do D&E when in same circuit, but cables from A & B to C are "dead"
I have many lights so its impossible to tell which are A & B as all work from same fuse

 

[andy63]

Maybe I'm misunderstanding?
Say you have got 3 original lights A - B - C and have added D (to C).
A, B and C work but D doesn't?
Have you ran a continuity test on the wiring after C to D?
Or have I got the wrong end of the stick?

Maybe I'm misunderstanding?
Say you have got 3 original lights A - B - C and have added D (to C).
A, B and C work but D doesn't?
Have you ran a continuity test on the wiring after C to D?
Or have I got the wrong end of the stick?

Not my understanding grant..
In your example A and B are still working but the supply from to C has failed.. and obviously D doesn't work as it spurred off C ..
Paul has disconnected the supply between B and C and rigged up a new supply to C and all work ok.. ie C and the new spurs D..
Odd but the existing supply is now open circuit. ..something has disturbed a connection or a wire is damaged..
Ta Andy.

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[Gellyneck]

I`m not sure from the wiring diagram which light comes before the one i used as a power source, but all the others work. I previously added two LED lights with no problem, its since I tried adding a 3rd that the power has gone to the light from which I accessed the power. Its hard to explain. But I added to ABC - D&E and all was well, since I added F only A & B work. If I put 12v to C it works fine as do D&E when in same circuit, but cables from A & B to C are "dead"
I have many lights so its impossible to tell which are A & B as all work from same fuse

OK. Have you ran a continuity test between B & C?

Oops, must stop doing that (now crossed with Andy)!

 

[Gellyneck]

Just another thought.
A - B working but B - C - D - E - F now not.
Have you tried running temporary wire from B - C and see what happens? Do they all work?

 

[andy63]

OK. Have you ran a continuity test between B & C?

Oops, must stop doing that (now crossed with Andy)!

Sorry Grant ill butt out... can't think of anything else Paul can do except to check the continuity as you suggest,but to do that he needs to know what fitting to open up at the other end... ie which light is B..
Hope you get there Paul
Andy

 

[paul18]

How would you do a continuity test between B & C if you dont know which is B? I`ll post some pics and see if it helps explain as I am struggling to do so
Pic 1 is ceiling lights operated from switch by door
Pic 2 is under counter switchable lights
Pic 3 is example of switchable light in bathroom
Pic 4 is example of switchable lights in bed area (excuse mess on bed!!)
Pic 5 is problem light (C)
Pic 6 is previous new light that worked fine (D or E (E is same on ther side of cab))

 

[Gellyneck]

Sorry Grant ill butt out... can't think of anything else Paul can do except to check the continuity as you suggest,but to do that he needs to know what fitting to open up at the other end... ie which light is B..
Hope you get there Paul
Andy

Don't you dare! I'm struggling as well.

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[paul18]

Cracked it! Had a furtle around down by the charging unit, (directly below light C in bottom of wardrobe) Found a fusible link amongst the dust etc with a blown 5 watt fuse in it. Changed the fuse, low and behold 13.5V across the cables to light C. I can only think that because the light is remote they ran a power source straight from the charger and hence its own fuse. The halogen bulb in C is 5 Watts, I put 3 LEDs on top of it drawing about 2 Watts in total, so when testing had all 4 on and overloaded the 5 Watt fuse. The independence of light C is not clear on wiring diagram. Its unlikely it will get overloaded in use as we never used light C as thats where our TV sits

Thanks for all your help guys, its no wonder that the problem couldn`t be solved!

 

[tonyidle]

Find out which one of the two wires (that now have no voltage on them) has actually failed: With the meter on the appropriate VOLTS range connect one side of your meter to a known good earth (metalwork or battery -ve NOT an earth wire). Connect the other meter lead first to one of your wires, then to the other. If you read battery voltage on one of the wires put it out of the way, move your meter lead (back) to the other one. Switch the meter to continuity. If you get a reading that wire is the earth wire and is intact. If not it means that only the earth is missing. If, on the other hand, you have no 12v supply to either wire perform the earth continuity test on both wires to see whether one of them is earthed and which one of the two it is.

If you have disturbed anything during your installation it is unlikely to have affected both wires and the above will show whether that is true or not. If you are certain all fuses are OK and that all appropriate switches are ON (in case your feed is from a switched light) then you are left with tracing the wiring. The wiring appears to be in trunking so it should be possible to get a good idea where it's coming from. Removing the fitting that appears to precede the new one that was working may well offer a wire to tug on to see if there's movement elsewhere. If the existing fitting you chose to remove turns out not to be the feed fitting remove the next most logical one. there is, in the end, no alternative to tracing the wires.

One thing that troubles me (and you from what you've said) is that the first new lights you installed worked OK until you installed this one. That doesn't really suggest that you have disturbed anything (and looking at your pics I can't see how you could anyway) which only leaves a possible blown fuse or a switch somewhere unnoticed that has been turned off. The fuse is unlikely but a re-check of any switches, if you haven't done so recently, is worthwhile.

 

[tonyidle]

Cracked it! Had a furtle around down by the charging unit, (directly below light C in bottom of wardrobe) Found a fusible link amongst the dust etc with a blown 5 watt fuse in it. Changed the fuse, low and behold 13.5V across the cables to light C. I can only think that because the light is remote they ran a power source straight from the charger and hence its own fuse. The halogen bulb in C is 5 Watts, I put 3 LEDs on top of it drawing about 2 Watts in total, so when testing had all 4 on and overloaded the 5 Watt fuse. The independence of light C is not clear on wiring diagram. Its unlikely it will get overloaded in use as we never used light C as thats where our TV sits

Thanks for all your help guys, its no wonder that the problem couldn`t be solved!

And I've just written a mile of text to try to help. You might have bloody waited!!!

 

[Gellyneck]

Cracked it! Had a furtle around down by the charging unit, (directly below light C in bottom of wardrobe) Found a fusible link amongst the dust etc with a blown 5 watt fuse in it. Changed the fuse, low and behold 13.5V across the cables to light C. I can only think that because the light is remote they ran a power source straight from the charger and hence its own fuse. The halogen bulb in C is 5 Watts, I put 3 LEDs on top of it drawing about 2 Watts in total, so when testing had all 4 on and overloaded the 5 Watt fuse. The independence of light C is not clear on wiring diagram. Its unlikely it will get overloaded in use as we never used light C as thats where our TV sits

Thanks for all your help guys, its no wonder that the problem couldn`t be solved!

Pleased you've sorted it Paul.
Been looking at your circuit diagram again and the only option I could think of was burnt out fuse or wire for the "C" light!

Oops. Blo*** crossed with Tony now. Gonna have to learn to read and type faster.

 

[TheCaller]

And I've just written a mile of text to try to help. You might have bloody waited!!!

Yes, but you were spot on with your last paragraph though!

Never mind, the rest of what you had written will be a good resource when someone else has a similar problem.

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[paul18]

Thanks Tony (and sorry for the wasted text/time), and all you others, for your help. It did seem logical to me that it was a fuse that had blown, but couldn`t understand how. Due to the remoteness of that light it was obviously easier to run power straight from charger via bespoke fuse

 

[Deleted34567]

Cracked it! Had a furtle around down by the charging unit, (directly below light C in bottom of wardrobe) Found a fusible link amongst the dust etc with a blown 5 watt fuse in it. Changed the fuse, low and behold 13.5V across the cables to light C. I can only think that because the light is remote they ran a power source straight from the charger and hence its own fuse. The halogen bulb in C is 5 Watts, I put 3 LEDs on top of it drawing about 2 Watts in total, so when testing had all 4 on and overloaded the 5 Watt fuse. The independence of light C is not clear on wiring diagram. Its unlikely it will get overloaded in use as we never used light C as thats where our TV sits

Thanks for all your help guys, its no wonder that the problem couldn`t be solved!

AKA ... open circuit.
Why I asked you to pin them out individualy using known +ve and -ve to determine what "line" was down.
Anyway, good you got it sorted.

 

[paul18]

Yes, thanks anyway. Wasn`t sure what you meant by open circuit! Best Tenner I ever spent joining this forum