I have a 2006 LR3 HSE. I recently have been having trouble starting the vehicle and when I'm driving the nav screen will go off and on. Also the heat and the radio does the same thing. It has always started but not like it should. I have tested the interstate battery and it was good, it has a alternator that is less than a year old and amps seem to be good and the starter is less than a year old both the starter and alternator are denso parts. I'm wondering could this be a problem with the negative battery cable? I know a few people stated that they have had problems with them. What do you think?

 

Surprisingly, it could be your brake switch from what I've read on here. Also, don't assume that a one year old alternator is solid... with everything being made disposable now-a-days everything is suspect. When I had my Excursion, it took the shop 3 alternators before getting one that produce enough voltage.

 

Brake switch doesn't usually mean trouble starting....but worth a look or change out since it's a $15 part. The negative cable is possible. Have you had any water ingress?

 

Alternator volts are in normal range, I guess I will try the breaklight switch I always keep a spare with me and no water issues!

 

Changed out my brake light switch and nothing changed I also forgot to mention that everything is clearing on my dash as well (trip odometer, mpg average, etc).

 

Yeah sounds like you have some kind of electrical issue that's causing a sort of "soft reset." I would check for water ingress in the common places and check in/around the battery for loose cables.

I've had the radio/nav shut off on me completely once or twice, where I had to pull the fuse.

 

Check main battery ground, check battery terminals, clean any connections that could be suspect etc. Try a hard reset too, (disconnect battery cables, hold ends together 2+min).

Not common, but sometimes when battery is changed nobody puts in another little vent tube that takes the vent gasses out of the area, usually not an issue when gasses vent but since they're trapped in the battery box they can react and corrode the cables exposed, sometimes badly.

Purportedly the PO on my D3 had this sort of issue and dealer replaced battery cables to correct.

 

So I had my battery tested again yesterday and the battery had a dead cell. Better yet there was only 1 month left on the interstate free replacement! So I got a brand new battery for Free!!! Thanks everyone for the help.