2006 LR3 battery/alternator issues
 

Yup, this is the same thread. So I ordered that fuse from Amazon so I will see what happens after I change that out. Also just keeping it on the charger overnight. But it does seem that the alternator is slightly undercharging at just under 14 volts so probably the spike in voltage was due to pilot error.

2006 LR3 battery issue
 

Hi again, I wanted to post a follow up to the thread for LR3 battery issues. So I did replace that 400amp battery fuse that you recommended and it seems to have fixed the issue with undercharging and battery light coming on! So thank you for that very helpful tip! And it was interesting that before, when I just removed the old fuse to examine and then put back in there was nothing that I noticed out of ordinary. And then when I replaced with the new fuse, and of course positive cable was disconnected, even just putting in new fuse and securing with end of cable in the box, there was just a faint spark when I touched the cable that made me think now this is working. And so far, no battery light and alternator charging at a steady 14 volts. Now I just have to flush the heater core to restore driver heat!

That is why I tend to recommend replacement too. If this really fixed your issues, I will put more emphasis on that going forward. I think they someone crack internally or such. Well gal things are working! Come back if anything changes, but hopefully not!

Well, I guess I spoke too soon, my son was driving today and the battery light came on again. I ordered a new tensioner and will replace that. I guess Land Rover recommends changing anytime you change the alternator and I did do that and the vehicle has over 170 k on it. If that doesn't do it, then I will have to take to a shop as my patience is wearing thin with this and we just need to have it working properly!

Well... crap.... FYI at 210k miles my tensioners are new. I have spares on hand for the one day I should replace em though.

Have we mentioned looking at the alternator connections? There is just one large positive connection then a small three wire, which is prone to break during alternator replacement. Maybe take a close look at things and make sure nothing is coming undone.

I would agree checking all cables and connections is what I would do next. Check all positive cables and all ground cables and their connection points. If you have the ability to check for voltage drop you can be more precise in your diagnosis amd not waste so much time. If you can't check for voltage drop (all you need is a good multimeter for that) then visually inspect every cable and connection for corrosion, and take all the connections apart, clean the mating surfaces to ensure good contact and reassemble. A spray of battery corrosion preventer on reassembled connections is a good preventative here also (I use the Noco brand but most anything similar will work). That won't fix a cable that has high resistance (which is why you should really do a voltage drop test on everything first), but it will help if a connection is the problem.

And don't rule out multiple alternators being bad - happens all the time.... A bad connection or a bad cable can quickly fry a new alternator and sometimes it takes several tries to find a new one that is actually good long term.

2006 LR 3 battery/alternator issues
 

Finally getting back to this thread in regards to the above! So I changed the tensioner for the belt that goes around the alternator and we haven't seen hide nor hair of the battery light on the dash! Also we have not had it on a charger for about two weeks so I'm gonna go out on a limb here and say it was the tensioner all along. And once the old one was removed, when you spun the pulley you could hear that it was not good. And then after I installed the new one and had to get the belt back on it and the alternator, you could feel the dramatic difference in how much leverage was required to take the tension off of the new one as compared to the old. And now I wish I had listened to Rock Auto when I ordered the new alternator as they said, " Make sure to check the tensioner as many people think they need a new alternator when it is really the tensioner that has failed!" So anyone out there who is being told they need a new alternator, Check the tensioner! And unfortunately you probably will have to remove it or at least take the belt off and spin the pulley. But the tensioner is a lot cheaper than the alternator and you will probably have to put one on anyway.