Hey guys, I am in desperate need of your help!
I bought a 2012 LR4 with 124,000 miles on it that ran but needed timing chains and coolant pipes fixed. Towed it home, replaced timing chains and all the cooling lines, water pump, thermostat, spark plugs, injectors, parking brake release button (drink spilled on it prior and didnt work) etc. Trunk ran great after I fixed it all. I cleared all the codes and saw I had a battery light on. Decided to get a new battery and this is when all the issues started.

I put in the new battery and the car was DEAD, no power to anything EXCEPT windows, seats and radio would turn on but not off. no screens even lit up. I thought it was needing the battery to be programmed to car, so plugged in my tool to program it and OBD2 port is dead, no power.

Put in old battery and same issue as new battery. Disconnected everything, let the car sit with negative cable off for 2 days, and same result. Started checking fuses and came across F63 in the glove box was blown. put in a new one and everything was good!

Drove it around and power steering was stiff so that was next.

Car sat out that night and it POURED! got in the next day and drivers floorboard was soaked. Car started up just fine and got it into the garage and started airing it out and fixed the drivers front drain tube.

Replaced all the valve blocks then too and started car to pump them back up from being deflated for replacing. All was good and was happy with progress.

now here comes the issue again. got a new PS Resevour and went to do a flush. Car is dead again just like before.
1) checked every fuse buy pulling and inspecting, as well as checking continuity and getting power.
2) checked every relay and bench tested them
3) I have power going to fuse box under hood
4) I have power going to alternator and starter
5) checked all ground straps and they are all good
6) replaced one ground strap from frame to trans on drivers side rear
7) checked all the ground studs for various things
8) pulled out CJB to inspect and looks good
9) pulled ECU and looks good
10) pulled the parking brake assist on drivers rear wheel well area and tried to see if can bus issue and that was it
11) pulled the other module on pass side rear wheel well area and nothing
12) pulled ABS module by drivers front area
13) pulled all modules under drivers seat and all good
14) checked alot of wiring for any damage and havent seen any

I am grasping at straws here as the car sits dead in the water with only the seats working, windows and radio goes on, but not off (have to pull battery to turn off)

 

It doesn’t sound like you were following the pinpoint tests and decided to replace or touch everything under the sun.
Not efficient and expensive.
So let’s start with this:
Humor us and provide the resting battery voltage.

 

resting battery voltage is 12.76

 

ok. clearly a fully charged AGM.
Next step, what codes are thrown

 

can’t check codes as the diagnostic port doesn’t have power.

it did have one code prior to this issue and that was low fuel pressure on start up

 

do you mean after you depress the start button, without depressing the brake pedal, its still dead?
A CAN bus failure??

 

thanks for the link to the PDF, going to read it tonight.

well i was guessing a can bus issue. when I open the door, nothing happens, no screens light up nothing, only the windows will work and seats will work. The radio will turn on and light up but not turn off.

if I depress the brake pedal and push start button nothing happens. all dead, no noises, no clicking, stone cold dead.

 

I think you'll need this too...

 

played around with that attachments and its definitely involved. What controls the DIC screen to wake up and start the car? The Radio works and touch screen but not the DIC

 

I like to confirm the “simple” first.
(I’m a software engineer by trade and have a strong background in support)

We did rule out the battery.
Can we rule out: was something knocked/disconnected when the battery was replaced?
Can we rule out the connections to the fuse boxes that were touched are sound?
Can we rule out that the removal of any module was properly installed without bent pins, dirt, etc?

You were successful at one point on replacing a fuse. So why you’ve started to muck with other components not related to the fuse, confuses me.
I would investigate the fuse circuit again, myself.

The screen has nothing to do with the starting of the vehicle.