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Electrical relay puzzle


DC_

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Happy Friday guys, ok I'm not the best when it comes to relays and electrics etc so please any advice make it child proof 😂 

Roofbar lights stopped working, checked fuses a while back and they came back on (loose fuse?) so anyway, they stopped again. I've noticed there's two replays on the heater box under the bonnet. The spot light wiring attach to them along with a number of other wires. 

Theres also a black wire coming from the alternator connecting into one of the relays along with two inline fuses. 

I did a bit of research about relays so know a little now. So the trouble is, I tried to change the relays thinking it could be a fault there, but in doing so I've muddled up the wires, when I put them all back on, I went to start the landy and only got a loud ish click..... so,did a bit more swapping and got it starting again ok, but, I have two wires now spare both thin black ones. One is that alternator wire and the other looks like it splices into the original harness. 😞😞 

 

if pictures would help I can take some later......

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the wire from alternator to the relay's is most likely the 12v power feed ign controlled for the relays, each of these should be earthed to body as well, or they will not operate,the diagram below should help, the relay terminals are numbered as shown. 

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Those black wires from the alternator really ought to be red or brown to show they're positive and permanently live.  They are the wires that feed to terminal number 30 or 87 on the relay, the wires to the lights going from the other of those two terminals (and should ideally also be red or brown, perhaps with a stripe to identify them).  

There will likely be some short earthing wires, hopefully with ring terminals rather than simply twisted ends in a loop, probably in light gauge wiring, and should be black, that should be connected to terminal s 86.  The trigger wire from the switch or the head lights should connect to the last remaining terminal, 85.  

All as per Ralph's diagram, your difficulty being recognising which wire is which if they are all badly colour coded like the positive feed.  A worry is your report that the wire from the alternator is thin, but it could be that the feeds are running from the battery lead post on the starter and they are using a bolt on the alternator casing as the earth (which would be correct in using thin black wire, but would not need a fuse).

Pictures would be very helpful.

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Thanks guys for the responses, ok it's two LED roofbar lights roughly about 20 inch in length each..... they are fed in from the roof through the bulkhead (joined together in the dash) so one wire from lights to connect (red and black). They operate on the full beam only and have no switch. I'm guessing the RED wire in the pictures is from the front loom going to the headlights? 

I put a multi meter on the wires during the week and discovered the other RED wire that's spliced into a green/purple wire has power. About 10-11 volts. 

The thin black wire from the alt is spliced into another.......

 

the ring connector has 3 earth wires running from it???

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OK, well having roof lights on a Defender switched with the main beam is illegal on public highways, including even unsealed roads (green lanes) - it's not the height, as many believe, that is the problem but the fact that they are behind the front axle (this is why many HGVs run them legally).  So, I'd strongly advise removing all the wiring associated with them and starting again from scratch with a dash mounted switch with warning light (either integrated in the switch or adjacent to it, but in clear sight while driving) to control the relays.  I know the warning light seems pointless as the lights will do a pretty good job of illuminating the bonnet (Honniton Hobbit's pet hate), but the lights could still be blinding to others during daylight.

 

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Thanks Snagger, I'm probably Gona do that. So now I need to figure out where the rest of the wires go? Can I do away with all of these? They're wired into the ignition so would it be just a matter of snipping them where they're spliced into the existing looms etc? 

 

Wiring them up from scratch seems a lot simpler 

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Trace every wire associated with them.  The power feed and relay earths can be binned, the wires to the light units put to one side for now, leaving the trigger wires.  Trace them to where they are spliced into the head light circuits and remove the splice, repairing the insulation as you finish.  You may need to remove the wrap tape from modified sections of wiring loom - its easier and neater to use flexible plastic conduit to tidy and protect the wiring on completion.

The black feed appears to be coming from the alternator diode pack that runs to the charge warning light.  I suspect that it was used as an automatic cut-out to kill the roof lights if the alternator wasn't providing charge.  Given that basic relays take up to 30A, I suspect they made a system that used one relay to cut power if the alternator was out, and the second relay, daisy chained off the first, was switched by the head lights.  That means the main current feed would not be the black wire.  If  had set it up that way, I'd also have a switch somewhere on the dash so that the lights can be left off or come on automatically with the high beam.  If you never knew about the switch, and it has been left in the on position, that would account for the previous owner not being eventually caught by the traffic police!

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Many thanks Snagger for taking the time to reply, truly appreciate it. 😊👍

all wiring now gone, relays now gone and rooflight wire tucked away safely until I get switches to wire it up properly with switch on the dash. 😎

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