andystephenson Posted October 26, 2014 Share Posted October 26, 2014 Hi Guys, I'm looking some help with my boot lights not working as per usual. About a year ago I added a second boot light and now have 2 smd led panels. They have been working great and super bright until recently they will only partially light up. The problem is intermittent as sometimes they work fine but most of the time they are very dimly lit. This morning I removed the boot panels to check the wiring and no amount of jingling the wiring would change whether they lit up properly or not. Unfortunately I don't have a multimeter to help me check at the moment but does anyone have any suggestions to where I should look next? Thanks in advance Andy 1 Quote Link to comment Share on other sites More sharing options...
alz Posted October 26, 2014 Share Posted October 26, 2014 Hi, Try the Earthing point undo it, clean and re-attach it. 1 Quote Link to comment Share on other sites More sharing options...
andystephenson Posted October 26, 2014 Author Share Posted October 26, 2014 Hi, Try the Earthing point undo it, clean and re-attach it. Do you know where I can find the earthing point for this? Thanks 1 Quote Link to comment Share on other sites More sharing options...
alz Posted October 26, 2014 Share Posted October 26, 2014 Andy, The main earth point you are looking for is in the tailgate, by the locking unit, you do need to take off some panels to get to it. if that does not fix it, disconnect the second light unit that you have fitted to see if it makes any difference. and did you use a stand alone earth for the second light unit.. 1 Quote Link to comment Share on other sites More sharing options...
alz Posted October 26, 2014 Share Posted October 26, 2014 Andy, Just checked in the book again the locking unit as small plug, so this means that the earth that you need to check is around the rear lights. that's not as bad should be no panels to move, just carpets by the lights. 1 Quote Link to comment Share on other sites More sharing options...
andystephenson Posted October 26, 2014 Author Share Posted October 26, 2014 Thanks for that alz, I've been out to the car and had a good look round the rear lights and couldn't see any obvious earth. Am I right in looking for a screw/bolt into the body? I also removed the side trim from the boot to try trace the wiring which I could only follow as far as when it starts to go behind the rear drivers side seat. Also the second light uses 2 scotch locks onto the wires for the first light unit, if I remove the second light the first does get slightly brighter but does not come on at full power. What's strange about it all is that they sometimes come on at normal brightness. http://imgur.com/a/3RsqE Cheers, Andy 1 Quote Link to comment Share on other sites More sharing options...
Dee_82 Posted October 26, 2014 Share Posted October 26, 2014 not sure its the same with all cars but with mine the boot lights work with 2 positive feeds rather than an earth point, when you shut the boot it sends a second 12v signal up the earth cable cancelling out the 12v from the positive feed, a meter would be really handy, if they are coming on dim then potentially that 12v earth line isn't getting cut off, or the 12v positive line might be lacking voltage. try putting in a wired bulb ands see what happens when the boot is closed and opened. 1 Quote Link to comment Share on other sites More sharing options...
troy45 Posted October 26, 2014 Share Posted October 26, 2014 The boot lamp on the Focus is fed from a 12V supply, through the battery saver relay. The -ve side routes through the tailgate latch which also has a switch in it for tailgate open/closed. From there it eventually goes to an earth in the left rear wheelarch, G77A. So, potential things to check if you can get hold of a multimeter - continuity on the earth side of things, 12V supply on the other pin, switch the LED's back to standard bulbs. Also, scotch locks are nasty horrible things and can damage the wire they're tapped into so this might be contributing to the problem. Quote Link to comment Share on other sites More sharing options...
andystephenson Posted October 28, 2014 Author Share Posted October 28, 2014 not sure its the same with all cars but with mine the boot lights work with 2 positive feeds rather than an earth point, when you shut the boot it sends a second 12v signal up the earth cable cancelling out the 12v from the positive feed, a meter would be really handy, if they are coming on dim then potentially that 12v earth line isn't getting cut off, or the 12v positive line might be lacking voltage. try putting in a wired bulb ands see what happens when the boot is closed and opened. Thank you both for that. I've tried with a multimeter this morning and when the boot is closed both wires are feeding 12v. When the boot is open and the lights are dim, the positive is feeding only 7v while the negative is at 0. Again, any amount of jingling the connections/scotch locks doesn't cause the lights to work/not work. They still are sometimes dim when the boot is opened, then randomly flicker to life, sometimes come on fine. Quote Link to comment Share on other sites More sharing options...
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