Lighting question: what's going on here?!

[Jonny2488]

My offside lighting unit currently does not work. I've had a look at the wiring and done a bit of fiddling around, but with no success.

I've got brand new 7 core cable and plugs on each end and know they're work as the nearside unit is fine (almost).

As I understand it, this system is "hard wired", any ideas what that is supposed to mean?? However, on further inspection it seems there is some wiring that is being directed out the back of the unit to make contact with the metal lighting board. Presumably this is just to earth it?

Would appreciate any clarification. See attached photos.

Next step is to buy a new unit I think.

Thanks,
J.

[ShinyShoe]

Brown wires don't look too great. Have you stuck a voltmeter across it?

[doggypaddle]

Originally Posted by ShinyShoe

Brown wires don't look too great. Have you stuck a voltmeter across it?

second that, looks fairly crusty. take the spades connectors off and clean all the terminals with a bit of emery paper till they're clean and shiny, also take the bulbs out and give the base contacts and sides a clean, replace the bulbs with new ones its easier then cleaning them! a good dollop of vaseline on everything will keep it from re-corroding.

[Jonny2488]

Haven't stuck a voltmeter across it yet. What should I stick it on and what should I expect to see?

Believe it or not, that photo was taken having done all that to every spade connector and corresponding connector, but to no avail.

What I'm struggling to understand is why the black/brown and white wires all seem to lead straight to the metal lighting board???

[Poly]

The white wire is the earth so its not unreasonable it goes to the metal body, although its not normal in my experience to earth the body of boat trailers (as the lights are easily removable). I don't understand why the tail lamp (brown and black) wires are also going there. Are you sure they actually connected to the metal? Its possible that there are (or were) running lights on the trailer which would be in that circuit:

http://www.wiringdiagrams21.com/wp-c...ng-diagram.png

[Tino]

9/10 times the fault is with the Earth (the white wire).
The earth cable is white and should be on the 31 pin on the socket.

The fact that NONE of the lights on that side work would indicate that the earth is the problem.

Check all the joints on the white wire... the plug for the car should be ok if the opposite light works. Try running a piece of wire from the white (earth) terminal to the opposite side light earth terminal.. that should is isolate the fault.

good luck

[Jonny2488]

Originally Posted by Poly

I don't understand why the tail lamp (brown and black) wires are also going there. Are you sure they actually connected to the metal?

I'm not 100% sure whether the wires actually make contact with the light board, but as you can see, they lead out of the back of the unit to the metal. I don't see why else they'd be led out of the back of the unit if they weren't meant to be touching the metal lighting board?

Originally Posted by Tino

9/10 times the fault is with the Earth (the white wire).
The earth cable is white and should be on the 31 pin on the socket.

The fact that NONE of the lights on that side work would indicate that the earth is the problem.

Check all the joints on the white wire... the plug for the car should be ok if the opposite light works. Try running a piece of wire from the white (earth) terminal to the opposite side light earth terminal.. that should is isolate the fault.

good luck

Thanks mate, will check all that over. Which earths exactly should I run the wire to/from to isolate the fault?

Thanks.

[ShinyShoe]

Poly has it - the wires are not earthing they must lead to another bulb.

Set it up to be on and stick a voltmeter across white (as close to where it comes out of the multicore as possible and each colour one by one. If you are getting 12V you know the earth is good down the multicore if not then you need to find where the multicore comes from. Presumably its not going from the socket it may be going to nearside and then through a junction to the off-side. Could be that junction thats the issue.

As has been suggested you might connect white to white on the good size - I'd just take a length of wire and connect it someplace to the white on the working side and then to the white as close to the bulb on the dodgy side... if that works you know its an earth issue. You've just got to keep moving the white closer and closer to the socket till you find a good connection.

[Rokraider]

Have you checked your vehicles socket? They often corrode away un noticed.

[Tino]

Originally Posted by Jonny2488

I'm not 100% sure whether the wires actually make contact with the light board, but as you can see, they lead out of the back of the unit to the metal. I don't see why else they'd be led out of the back of the unit if they weren't meant to be touching the metal lighting board?



Thanks mate, will check all that over. Which earths exactly should I run the wire to/from to isolate the fault?

Thanks.

You might try new bulbs first!

First the colour codes:
white = neutral or Earth.
bLack. Left hand Tail Light and Number plate
bRown: Right hand Tail Light and Number plate
Blue; Aux in this case FOG lamp
Red; Brake Light
yeLLow; Left Indicator
gReen; Right Indicator

Just run a cable to any of the white terminals on the other side...they all earth so its easy.

If you buy a 12 volt Phase tester (pic attached) in your local motor factor it will help. Clip the end onto the negative o r earth terminal and prod the live terminal you want to test..the bulb lights if its live.

You might try new bulbs first!

[ShinyShoe]

Originally Posted by Rokraider

Have you checked your vehicles socket? They often corrode away un noticed.

brake lights work on the other side though...