Have a 2008 LR3. Battery drains with no pattern - could happen in 3 weeks, could be tonight. LR has yet to figure out what it is but was happy to charge me a bunch of money guessing.

Does anyone know if the LR3 has a ECU relay for the main computer? I'm wondering if it's a sticky relay problem but I have not found what I am looking for on the relay diagrams.

 

how old is the alternator? If the diodes short the alternator can drain the battery overnight.

 

LR just put in a new alternator. Before that, it had the original, then I installed another one then another one. All 4 alternators didn't help the issue lol.

 

Yeah I think we can eliminate the alternator!

 

You try swapping in a new battery to see if it persists?

These trucks get all squirrelly when the battery is on its way out

 

Any aftermarket electrical items, especially any sort of aftermarket alarm or remote start device? Like a couple others have said as well could possibly be a failing battery, especially if just one cell is failing.

If you know your way around a DVOM I'd do a voltage drop test. This is a little tricky on these LR3's because some of the fuses are inside so you need to find a way to keep the vehicle asleep while the door is open so you can access these fuses during the test. And if you haven't already bypassed it you need to jump your pins in the hood switch as well so the car thinks the hood is closed. This also brings me to the point of if your factory alarm randomly goes off there is a really high chance your hood switch is bad if you have not bypassed the hood switch yet.