I wanted to follow up on this one as I am having the same issue now with the shifter plate D remaining lit at all times, even with the car turned off.
In my case, I left the sunroof vented (popped up, not fully open) and we had torrential rains all night long. When I got in the LR3 I noticed light coming in and that is when I realized I had left the sunroof open. I looked around and to my surprise, everything looked bone dry. I was thrilled.
Then when I started the LR3 and pulled away, I got a transmission fault message on the dash. It did not affect the driving, so I figured I would look into it later. Mid-day my alarm when off by itself. At that moment, a tree chipper truck was operating just 20 feet away and I thought maybe the virbations from it running triggered it.
Then, when I went to get into it an hour later, I turned it on and got the F message in the dash along with limited gears available. I had to manually release the shifter to be able to drive it. Plus, now when I take the key out, the Key in Ignition message appears and the key chime continues to go and the radio does not shut off. I also cannot lock or unlock the doors with the FOB.
I had been having the TPMS light randomly flash on and off for about 2 weeks prior to this, so I thought maybe my battery was starting to hit that funny spot where things go wrong. Since it was just about 3 years old, I decided to just replace it with the same factory spec Interstate battery. Problem did not change.
So then I removed, dissassembled, and cleaned the brake switch since I read about that issue, but no luck. Removed kick panels, things look dry and in mint condition there. Already replaced the cowl just 6 months ago, but checked and no issues there.
Then I found posts about spilled drinks and such and these issues, so I removed the center console and although it is a bit dirty, I see no tell tale signs of water. When I lifted the center console box cover, however, I did notice a few drops in the little indention under the latch (see photo). So water must have gotten in and evaporated.
I took apart the connectors and when i disconnected the large white one, I noticed the key chime went off!!! Then, as I was wiggling wires, it came back on again, then off, then on, etc. Ok, progress! So I took some canned air and puffed it into the connectors and harnesses and into the gear shifter itself and after that I could no longer make the chime come on. I figured I must have knocked out whatever moisture was still sitting somewhere. Yeah!
When I connected the center console again and started it up, everthing was good! Then after a minute of driving however, I got a transmission error message again in the dash, same as the first time I drove it. Drives fine now, but once it got dark, I realized the shifter plate light is stuck on D and it does not turn off even with the key removed. When I disconnect the harness underneath it goes off, but as soon as I just barely touch the harness to the plate again the D lights up and never changes.
All of the other symptoms are gone, the FOB works, the alarm is not going off, the truck drives fine, but I get the message and the light does not move.
So, I unsure how to troublesoot from here. The harness that goes into the bottom of the gear shifter does not feel like a plugged harness and I cannot get it loose - I am fearful to rip a wire out if I pull too hard. Since that seemed to be where the issue was stemming from I wanted to pull it out and blow air in there. I took all the other connectors apart and used a compressor at work to blow air in all the connections and nooks and crannies but no luck, although it did get the area pretty clean!
Any thoughts on what to try next. I see that I can order just the shifter plate for about $65, but before I throw money at parts, I wanted to see if anyone had any other suggestions. If the plate itself was shorted, it that a permanent thing or might it still dry out, or should I take it apart in put it in an oven for a while?
Although the parking brake, air suspension and range selectors all work, could this be related to wiring elsewhere? Replacing the whole console is @ $250, so I do not want to go there unless I can prove I need to.
If anyone has any suggestions I would appreciate it!