blown fuse trailer reverse lights not working

[coopers1969]

Hi Guys

at my wits end hope someone may be able to shed some light. Tonight i was hooking up a led work light on the back of the trailer. as i only have a 5 core trailer wire so am i having to runs separate wire to connect the LED worklighs, i have connected the wire to Number 2 (reverse socket) plus the earth on the trailer socket, no lights. Checked if there was power at the socket at the car with a vault metre all goods 13.8 to 14.1 volts, OK we have power so properly an issue with the lights.
the problem is the earth and red wired touched and sparked and now no power at the car socket. :(
Check the fuses in the left hand panel non blown. Checked the fuses under the glove box i think No 6 relates to the reversing lights on the trailer and the fuse isn't blown.
i dont know where else to look, but the socket at the car is now reading 0.00 volts.
Any ideas guys??

oh it is a Disco 3 2008

[Meken]

Try a hard reset the short may have upset a computer somewhere
Do the other trailer lights still work? I think there's a fuse inside the trailer ecu - not sure where the trailer ecu is in your model - search on here for trailer ecu

[sniegy]

If you were running power for the LED light from pin 2 (Normally Reverse but the D3 is a Fog Light Circuit) & Earthed you may have blown the Rear Fog light circuit ??

HTH
Cheers

[coopers1969]

Try a hard reset the short may have upset a computer somewhere
Do the other trailer lights still work? I think there's a fuse inside the trailer ecu - not sure where the trailer ecu is in your model - search on here for trailer ecu
hi Meken


yeah the other trailer light do work so it is really weird. will have a look though the forum for the trailer ECU thanks for the input, need all the help i can get.

[coopers1969]

If you were running power for the LED light from pin 2 (Normally Reverse but the D3 is a Fog Light Circuit) & Earthed you may have blown the Rear Fog light circuit ??

HTH
Cheers

Hi Sniegy

i though the same thing so i replaced the rear fog lamp fuse (which seemed to be fine) in the rear quarter panel and still nothing. this really has me stumped.

[Graeme]

Have you checked fuse 44 (15A) behind the glove box? It supplies the trailer fog light fuse.

Have you checked for power at both sides of the trailer fog light fuse?

Edit: Being fog lights the rear fog lights wll have to be switched on.

[coopers1969]

thanks Graeme

will give all these a go tomorrow though plug 2 was working even without the rear fog lights on before i shorted the circuit out. it worked when i put the car into reverse which i assume based on wiring diagrams is plug 2 in a trailer wiring circuit.
thanks again. will report back once i have checked these things.

[Graeme]

Sorry, I didn't realise you were using the 2nd plug, thinking you were using pin 2 of the normal plug which is trailer fogs.

Perhaps the trailer reverse relay in the passenger fuse panel has failed.

Would you not do better using either the permanent or iginition power from the 2nd plug instead of reverse?

[coopers1969]

Hi Graeme

i will check the relay next. and yes i am using the 2nd pin in the trailer plug which is there reversing pin (black wire) and the reason why i am trying to use this pin to connected to the separate LED work Lamp is so that if i am reversing at night time to a camp spot i can see better to what is happening behind me also when reversing into the yard which is tight it helps me see. As for the permanent or ignition pin wouldn't this blind people behind me while driving or can you turn it off. Can i use the white plug?
trailer wiring diagram (http://www.campertrailers.org/trailer_wiring_diagram.htm)
i have attached a link to make my self a bit clearer sorry i think i was making this harder with pin and plug terminology.
i have checked the No 6 fuse in the passenger fuse box which is the trailer reverse fuse. when you say relay is that different to Fuse? And all other lights work on the trailer.

thanks again Graeme for your help and suggestions :)

[Graeme]

Pin 2 of the black plug is used trailer fogs according to the 2007 D3 and 2010 D4 wiring diagrams, with pin 1 of the white plug for the trailer reverse.

Here's the wiring diagram for the D3 trailer socket:
81246

[Meken]

Hi Graeme

i will check the relay next. and yes i am using the 2nd pin in the trailer plug which is there reversing pin (black wire) and the reason why i am trying to use this pin to connected to the separate LED work Lamp is so that if i am reversing at night time to a camp spot i can see better to what is happening behind me also when reversing into the yard which is tight it helps me see. As for the permanent or ignition pin wouldn't this blind people behind me while driving or can you turn it off. Can i use the white plug?
trailer wiring diagram (http://www.campertrailers.org/trailer_wiring_diagram.htm)
i have attached a link to make my self a bit clearer sorry i think i was making this harder with pin and plug terminology.
i have checked the No 6 fuse in the passenger fuse box which is the trailer reverse fuse. when you say relay is that different to Fuse? And all other lights work on the trailer.

thanks again Graeme for your help and suggestions :)


I see the problem - you are using aus standards pin designations & wire colours. LR don't follow all of those pin designations... Ask Pete(sneigy) for a diagram (actually I think he posted one earlier) or explanation of what each pin does

[coopers1969]

thanks Graeme for the diagram, though i found the problem see photo attached. there is a fuse at the battery terminal (yellow wire) which must have been put there and connected to the rear plug at pin 2 position by the previous owner cause once i changed the fuse and put the car in reverse tested Pin 2 again WE HAVE POWER!!!
re connected and all is working rear LED spot lights and all other LED trailer lights.

thanks again Graeme

[Graeme]

Good that you found that fuse. If the fuse is attached to the battery terminal then it must be switched by a relay operated by a reverse feed, either directly from the reverse light supply or from the trailer reverse lights supply. It seems a round-about way to get power to that trailer plug wire, being simpler to have done it in the left rear corner.

[coopers1969]

yeah couldnt agree more use a connection at the back of the car and putting the fuse down there makes a lot more sense, Oh well just another little quirk of buying a second hand Disco.

[Meken]

Best practice I've read is to fuse each end of long run of heavy cable - maybe the previous owner had something heavy duty he plugged in.