So here's my OG thread that started with trying to pin down the source of a parasitic battery drain: https://landroverforums.com/forum/di...-right-124887/

I've narrowed down the problem to the Disco thinking the key is still in the ignition after it's removed.

- When trying to lock the Disco with the key fob button, it honks like it does with the key is in the ignition and will not lock.
- The dash lights remain on in the position just before cranking.
- The draw on the battery is about 3500-4000mA but goes down to spec levels if I...

...fidget with these wires coming out of the ignition switch in the photo below. Gently moving them a little without the key in the ignition can sometimes make the dash lights turn off and function just like it should without a key inserted. It's not all the time, but sometimes.

Video of the issue too:

 

OK I've singled it down to moving just the yellow wire.

 

Nicely done man, gettin closer! Now you just gotta figure out if the issue is in the wire itself, the solder joints, or the switch internally, to state the obvious, lol. I'd bet it's the switch, but I wouldn't rule out the solder joints either. I'd test the switch by unplugging it and figuring out what pin does what, and test for continuity when it shouldn't have it as the key is turned. If that tests fine, the check the solder joints by testing continuity thru the connector. Then check wiring if you haven't found the issue by then. Anyway, good luck, you're makin progress

 

I had and still have a similar issue. I think my ignition barrel is worn out. Too lazy to replace it. It happens like once a week for me, but usually jiggling the key while its still in fixes it for me.

 

There is a lever in the igniition barrel that actuates a switch to turn on the chime for leaving the key in the ignition. It sticks occasionally, probably somewhat related to wear in the barrel. Never see it cause the lights to stay on before.

 

OK so made some progress today. There happened to be a Disco at the junkyard today, so I zoomed down there and unbelievably there it was... the switch! But then upon closer inspection, some gorilla who got there before me pried it off to get to something else. So though the switch was indeed there, it had a big part of the plastic housing broken. Either way, I took it, brought it home, and disassembled it to figure out how it works and what could be the potential issue with my current one.

I tested continuity on my existing switch to rule out bad solders and bad wires, all looked good. (To future searchers, to test, set your multimeter to read ohms, place one probe at the solder and one at the terminal brick (brown plug) and make sure there's little to no resistance.) So I deduced it had to be something inside the switch. So, no going back now, it's already broken, I pulled it all apart.

What I found was a pretty filthy contacts situation, in addition to two little pins that had broken off. Thankfully I had the junkyard switch that was all good internally, so I swapped over the part that was broken, cleaned and regressed with silicon grease. I tested the detent movement and it feels SO much smoother than it did before. I found teeny tiny M3 nuts/bolts at ace to replace the rivets I had to drill out when opening the switch case up.

It's on the bench now ready to be reinstalled. Will test tomorrow and report back.



Junkyard switch on top, my existing switch on the bottom. That recess receives a lug that the key is mechanically turning. Wild how much more worn out the junkyard switch is in this regard.

Broken legs on my existing switch.

Junkyard switch on the bottom. Notice how the little legs broke off on my existing switch.

This is the spring that you press against when cranking.

Cleaned and assembled. Junkyard housing on the bottom.

Filthy contacts on my existing switch.

All cleaned up.

Solders all good.

Little M3 bolts.

And nuts.

 

Wow man, excellent documentation, so many great pics and so much great info, really nicely done. This post should come in handy for lots of folks down the line. Nice to see yet another one of the Disco switches is repairable. Subscribed in case I ever need to reference it

 

Welp, closing out this thread for now! Repaired switch is reinstalled, lights and all function like they should, and pleased to report the parasitic draw is within Land Rover's spec. Turns out those broken contacts were just randomly causing the switch to remain in the powered-on position. Crazy how these off-road capable, multi-ton beasts can be brought down by a piece of copper no bigger than a staple.

Technically a little bit over, Disco 2 should be 35mA, but I'll take the W for now.