Georgeblade

Active Member
Hello,
I'm having a hair pulling out moment.

My 200tdi developed a lighting earth fault that I can't find.
So after much trying and failing I have wired the grounding points for each light direct to the battery -ve (4 wires).
It solved the problem, the sidelights don't flicker in time with the indicators.
Except - with a foot on the brakes, it still foes the flickering thing.
I have replaced the flasher relay, and tries a different stalk switch, and different tear light clusters - all to no avail.
All help gratefully received.
 
Try cleaning up the rear light sockets or whatever the bulbs fit into and the terminals on the sockets(never owned a disco so no idea of the set up) then fit new bulbs.
 
Try cleaning up the rear light sockets or whatever the bulbs fit into and the terminals on the sockets(never owned a disco so no idea of the set up) then fit new bulbs.
Hi Flossie,
Yep had a go at that, got some replacement bulb holders from a breakers - no difference.
I also tried different light clusters - no difference.
Its baffling.
 
Hello,
I'm having a hair pulling out moment.

My 200tdi developed a lighting earth fault that I can't find.
So after much trying and failing I have wired the grounding points for each light direct to the battery -ve (4 wires).
It solved the problem, the sidelights don't flicker in time with the indicators.
Except - with a foot on the brakes, it still foes the flickering thing.
I have replaced the flasher relay, and tries a different stalk switch, and different tear light clusters - all to no avail.
All help gratefully received.
Were the indicator, stop light and side/tail light come together is the rear light units, and the iffy earth on one of the units, a simple test is a wire from the metal bulb housing frame to a nearby earth connection… a door hinge bolt possibly.
 
Were the indicator, stop light and side/tail light come together is the rear light units, and the iffy earth on one of the units, a simple test is a wire from the metal bulb housing frame to a nearby earth connection… a door hinge bolt possibly.
So, I've run new 25amp black wire from the light cluster earth wire direct to the Battery -ve for both the rear light clusters and each of the headlights.
It sorted the problem if sidelights flashing with the indicators but hasn't stopped it once the brake lights are on.
Its baffling as the lights are now all directly earthed on to the battery.
 
So when the brake lights are on the side lights come on too? Or.....
When sidelights are on and an inducator is on when I touch the footbrake they all start flickering in time with the indicator. It also happens when reversing lights are on.
It doesn't happen when sidelights are on, and rear fogs are on when indicating.
So it seems to be only when a light activated by a remote switch (brakes and reversing) that causes the flickering in time with indicators.
 
Baffling indeed. I'm no expert and before forums and Google etc I worked electrical problems out mostly by elimination. Disconnect reverse / brake light switches and try it then?
 
Sounds like the brake lights are the issue...earthing down the indicator channel?
:)
That's kinda whete my head is too.
Just had another look at the wiring diagram for a '93 Disco, and the brake lights and reversing lights switches have a common feed.
Time to look at the wiring in that neck of the woods as I did replace the reversing light switch on the gearbox a while ago.
Thanks fir the prompt.
 
Baffling indeed. I'm no expert and before forums and Google etc I worked electrical problems out mostly by elimination. Disconnect reverse / brake light switches and try it then?
Good call.
I'll start with the reversing light switch.
I've also ordered a new brakel light switch as my one is a bit wobbly and seems to be leaking what looks like very light oil.
 
If you have a trailer socket you should inspect that too
Yup, rewired a new socket even all this started but no impact.
Today I spliced the trailer socket earth onto the rear light cluster earth. Doesn't seem to have changed anything.
However, I'll unplug it from the car loom tomorra to see what happens - worth a try.
Many thanks.
 
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checked your headers for water ingress and damage
 
Does the main fuse box have earths to body/chassis/engine? Not familiar with D1 but my old D2 gave me problems with the fuse box/body earth.
 
Does the main fuse box have earths to body/chassis/engine? Not familiar with D1 but my old D2 gave me problems with the fuse box/body earth.
Not sure, there us only 1 fuse box on a D1 ppre-facelift, behind a panel in the drivers footwell.
I've unscrewed the fuse box a couple of times to get access to relays behind it, but never noticed an earth.
I'll have another look.
 
I can see at least 2 headers hiding under the front dash.
Looking at them from the outside they look dry and fine.
I'll investigate further......
 
Sorted!
It was a volt drop on the ground side and a volt drop on the supply side.
The clue in the supply side was the shared fuse between rear indicators brake lights and reversing lights.
Basically it was old wires behind the fuse panel in the drivers footwell setting up some sort of interference with each other.
Split the circuits, installed a relay, fixed.
 

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