Earth issue

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Dutchy7

Active Member
Posts
125
Location
Texas
I have a 1990 Defender 90. RHD. I put RDX led lights on for the signals, running lights and brake lights. I am having the issue of my head lights being on and my left blinker not working. Right blinker works just
Fine. I turn the head lights off and it works. Head lights coming on cause it to stop. The running lights sometimes cause it to stop. I found three earths that were not connected. One on the engine to the body, fixed not the cause. One on the inside of the dash that was for the windshield wiper, fixed and not the issue. And one brown one on the inside of the engine that's now connected and is not the issue. Please help. Where could this earth be?
 
I haven't worked on front area wiring on a Defender, but on my SIII the earth wire from the left wing came across by the top of the radiator and joined in with the right wing earth on the right inner wing by the radiator somewhere. If that wasn't original, that's certainly how it was when I got to it. Defender probably the same.

I think that connection might be your problem.
 
I haven't worked on front area wiring on a Defender, but on my SIII the earth wire from the left wing came across by the top of the radiator and joined in with the right wing earth on the right inner wing by the radiator somewhere. If that wasn't original, that's certainly how it was when I got to it. Defender probably the same.

I think that connection might be your problem.
I wish I was savvy with this. So I know what one your talking about. What would be the problem. Or just mess with that ground? Idk. I'm lost.
 
Take the connection apart and clean up all the contact areas at that point. Put it back together with a bit of Vaseline to protect it. What that does is to properly connect the left earth to the right one and the inner wing. As built, the inner wing was also connected to the chassis, and should provide an earth path of its own, but corrosion will have done for that, so you'll now be relying on the right earth alone. Not ideal, but it works.
 
I don't like the not ideal. So just
Trace the earth from the area that Its not working and see if that's it? You talk about the inner wing what is that? I like things to work as they should. Where usually do they hide the earths for the lights? I'm sorry if I'm not tracking. Electrical is like rocket science for me. Thank you for all the help.
 
Each wing assembly is made of three parts. The 'outer wing' (the bit that you can see with the bonnet shut) is two pieces joined just above the headlamp. The inner wing is the panel that attaches to the radiator panel, chassis etc.. and stops water and dirt being flung into the engine space. When you unbolt the wing, all three bits stay together. Electrical continuity was provided by all the screws holding it onto the car, but corrosion will have ruined the certainty of them. You could go and take the wing off and clean it all up, but then you should really do that all over the rest of the car, because that's more or less in the same condition.

If you want to make a return path as effective as the original, get a new wire of cross section equal to double (or more) the size of the earth connection for each front lamp set. Connect it to the earth point that we're discussing and run it back to an earth point on the engine.
 
Each wing assembly is made of three parts. The 'outer wing' (the bit that you can see with the bonnet shut) is two pieces joined just above the headlamp. The inner wing is the panel that attaches to the radiator panel, chassis etc.. and stops water and dirt being flung into the engine space. When you unbolt the wing, all three bits stay together. Electrical continuity was provided by all the screws holding it onto the car, but corrosion will have ruined the certainty of them. You could go and take the wing off and clean it all up, but then you should really do that all over the rest of the car, because that's more or less in the same condition.

If you want to make a return path as effective as the original, get a new wire of cross section equal to double (or more) the size of the earth connection for each front lamp set. Connect it to the earth point that we're discussing and run it back to an earth point on the engine.


Alright I'm completely lost now. So clean up the front end where the lights are at. Check the line coming from the driver side wing to the passenger side wing and ensure that it's working? I would have to check all grounds in the front of the defender as that is where it most likely would be coming from. Let me know if I'm wrong. I just want to find this earth that is causing the issue.
 
Had this same issue (though not with LEDs), it turned out to be one of the Earth cables on the affected side for either the head light, sides or indicators (can't remember exactly which one, sorry) but the earth cable had snapped. It turned out to be I had reattached it at the wrong point of the connector that joins up all of the Earths for the lights on that side.

Check your wiring to make sure everything is connected along 'in order' (basically so the headlights or sides don't pull your indicator low inadvertently.
 
As I said, I think the earth wire comes from the left light cluster across to an earth point on the right inner wing near the radiator. The right lamp cluster will earth to the same point. Find that junction, take it apart and clean it up. Reassemble with vaseline. If you want to do a better job, run a new thicker wire from there to a point on the engine - routing it to miss moving parts and leaving a little slack to let the engine move about without breaking it.
 
Gentlemen. Happy to say it was the signal itself. One of the wires came loose and i didn't notice it. Put it back on and turned things on and it worked. I appreciate all of your help and patience. Thank you all again.
 
Just kidding. Back to square one again. Taking out the lights and reconnecting them to see where the disconnect is. Somewhere on the left side as that's the turn signal not working when the lights go on. It will work when I turn the signal on with lights off and then turn the lights on. There is no wire going across the radiator. Need your help again. Thanks guys
 
try with the head light earth on that side disconnected
connect it all back up and again, then repeat for side light earth disconnected
repeat again for the front side indicator earth

see if that directs you to he fault
 
Alright. Connected the ground on the driver side, the side that works. Still does the same thing. When turning the lights on the signal stops working. Any suggestions now?
 
how are all the earth's for the lights on the non-driver side connected, is there a big connector they all go into? Can you get a picture of it?

Yes it has the three connector the original I'm assuming.
 

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Is there one of the connections on that block the earth lead that goes to the chassis/earth point/not one of the light earths?
If it is, are all the light earths connected at one end of the connector and the earth lead that goes off to the chassis or where ever connected into the opposite end.
This is basically the issue I had, shouldn't make a difference, but vehicle wiring is never "normal" :rolleyes:
 
Is there one of the connections on that block the earth lead that goes to the chassis/earth point/not one of the light earths?
If it is, are all the light earths connected at one end of the connector and the earth lead that goes off to the chassis or where ever connected into the opposite end.
This is basically the issue I had, shouldn't make a difference, but vehicle wiring is never "normal" :rolleyes:

Yes but It goes in to the harness that leads to the firewall. There are grounds that come out of the harness that go directly to the vehicle up front here. Where would I find the earth for this harness near the cabin? Here's a better image. Now from that cluster the ground leads to the front of the engine bay in that harness. Make sense?
 

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Aye, those 3 that are coming off are for the earth point for that part of the engine bay, the point they go to is the earth point for your lights, what comes out of the harness to that connector should essentially be a line that goes back to the those 3 that go to earth point. It still sounds like you have an accidental earth path being created when you turn the headlights on, as the indicators work with the headlights off then they are clearly connected to an earth.

Unfortunately, without tinkering myself I'm out of ideas, Texas being a bit far..
 
Aye, those 3 that are coming off are for the earth point for that part of the engine bay, the point they go to is the earth point for your lights, what comes out of the harness to that connector should essentially be a line that goes back to the those 3 that go to earth point. It still sounds like you have an accidental earth path being created when you turn the headlights on, as the indicators work with the headlights off then they are clearly connected to an earth.

Unfortunately, without tinkering myself I'm out of ideas, Texas being a bit far..


Mention I have a side marker led. I took all the lights and put them in the same place as the other lights for the earths. Leaving the side marker out. But my driver side is the same with no issues. And again same issue. It turns off when the headlights come on. Much appreciated. I think I messed with it enough and have to take it to a professional. Thanks for the quick response.
 
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