Anderzander Posted January 15 Share Posted January 15 I’m sorting out my trailer wiring and have found the wiring won’t take any solder. I’ve cut far enough back that I’m away from any oxidation, but stripped back it has a black colour on the wire on its whole length. A skotch pad cleans it to shiny(ish) copper .. but it still won’t solder. It just runs off. I’ve had this before on old British motorbike wiring - on those I’ve found just lots of heat gets there - presumably burning something off, or I’ve just replaced it all. Any suggestions please? Plan B is going to use crimped connectors - not ideal as I need to reinstate a little resister that was in there. Quote Link to comment Share on other sites More sharing options...
steve b Posted January 15 Share Posted January 15 Flux paste usually does it when the wires are a bit old and tarnished. Steve 1 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 15 Share Posted January 15 41 minutes ago, Anderzander said: I’ve cut far enough back that I’m away from any oxidation, but stripped back it has a black colour on the wire on its whole length You're not away from oxidation then? I have a little pot of flux paste as Steve says, which sometimes works, although TBH just crimping a connector on instead would usually be my choice in that situation - then cover it with glue-lined heat shrink. Quote Link to comment Share on other sites More sharing options...
Simon_CSK Posted January 15 Share Posted January 15 What I have done in the past is twist fresh wire into the wire to be soldered giving the solder something to ahrere to. Quote Link to comment Share on other sites More sharing options...
JeffR Posted January 15 Share Posted January 15 Try acetic acid, white vinegar has worked for me in the past, not always, but most of the time. Dip wire end in a pot for an hour or two then rinse (may need a repeat). Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted January 16 Share Posted January 16 Active flux which is acidic and supposed to clean the material as well as being a flux. Mo 1 Quote Link to comment Share on other sites More sharing options...
pete3000 Posted January 16 Share Posted January 16 If it's gone that far the chances are the PVC or rubber insulation has probably gone brittle. Time to put some fresh in? Quote Link to comment Share on other sites More sharing options...
Anderzander Posted January 16 Author Share Posted January 16 Thanks all - great input as always. The wiring seems in good order in all other ways… I’ll start with some flux, if that doesn’t work I’ll try some crimps. I made a mistake though - it’s not a resistor, it’s a diode. I should have paid more attention to which way it was fitted. Quote Link to comment Share on other sites More sharing options...
Ed Poore Posted January 18 Share Posted January 18 Bear in mind that some wires are very very difficult to solder. We recently tried out a reel of CCA (Copper Clad Aluminium) and that's unsolderable by any normal means, intended for crimping only. What you have might be the same given trailer wiring is normally intended to be in screw terminals or crimped. 1 Quote Link to comment Share on other sites More sharing options...
Anderzander Posted January 18 Author Share Posted January 18 That would make sense because the coating doesn’t look like corrosion. Quote Link to comment Share on other sites More sharing options...
Anderzander Posted January 20 Author Share Posted January 20 So - I’ve crimped the wire into half a crimp terminal and soldered the diode in. the solder isn’t bright - and the wires outside of the crimp are a little open .. probably because my eyes aren’t what they were .. but I think it’ll do. 1 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 20 Share Posted January 20 Neat job, should be good. 1 Quote Link to comment Share on other sites More sharing options...
Anderzander Posted January 20 Author Share Posted January 20 Thank you - that’s very encouraging. Quote Link to comment Share on other sites More sharing options...
TD5toV8110 Posted January 20 Share Posted January 20 What's the purpose of a diode in your trailer wiring? Stop back feed to the car? What and why? 🤔 Cheers Dave Quote Link to comment Share on other sites More sharing options...
fmmv Posted January 20 Share Posted January 20 There's an argument to feed all trailer lights especially indicators through diodes, to stop criminal ace wholes from backfeeding through the plug, which might or might not affect alarm arrangements. Or maybe have a switched plug. 1 Quote Link to comment Share on other sites More sharing options...
Anderzander Posted January 21 Author Share Posted January 21 I did wonder that myself - at first I thought it was in case the purple permanently live wire shorted and fed back .. but that red/yellow wire is the fog light and its warning light, which is spliced back into the dash and the ECU. Quote Link to comment Share on other sites More sharing options...
Anderzander Posted January 21 Author Share Posted January 21 Not the full circuit / but you can see the wires and how it reaches the dash and ECU. Quote Link to comment Share on other sites More sharing options...
fmmv Posted January 21 Share Posted January 21 There are relays designed for CAN vehicles that are triggered by vehicle lights but switch an independent power source. It occurred to me one might use something like that and cut off its power except when towing to prevent access to electrics. Quote Link to comment Share on other sites More sharing options...
PaulMc Posted January 21 Share Posted January 21 This is how Land Rover's harness manufacturer (Leoni Wiring Systems) insert a resistor in the illumination live on a 300Tdi Defender clock harness (AMR1647) They use open-barrel splice crimps and clear heatshrink. . Quote Link to comment Share on other sites More sharing options...
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