QUOTE (A_Null @ Jun 20 2010, 12:30 PM)
Assuming that the battery is clean, the battery terminals are not corroded, and the electrolyte level is good... you HAVE checked these, right?

If the battery does not have enough power to crank the car under normal circumstances, there are a couple of basic things that can happen. Either the battery is not being sufficiently charged, or something is allowing that charge to drain away. You say that it is charging back up, so it must be that something is allowing the charge to dissipate. It's either internal to the battery, or external - meaning some part of the wiring system connected to it. Internal usually means one or more shorted cells, and a new battery is in order. External (within the wiring) is most often something left on, like lights or some new stereo amp, etc., or a problem with the alternator. Sometimes one of the diodes inside the alternator can short out and provide a current path which will drain the battery. And most times, a single failed diode will still allow the alternator to charge when running. It doesn't charge as well, but you won't be able to tell that without test equipment.

Generally speaking, an auto parts store will be able to test for all of these problems quickly and easily, and most will do it for free. Park up front, next to the storefront, and just go in and ask.

************************************************** ***********************************************



Do You Think This Is My Problem ??? >>>> failed diode
My 04 XG 350 L With 22000 Miles On It Has A New Battery 2 In 2 Years ,, It Keeps Going Dead.

I Took Out The Add on Alarm , Thought That Was It But It Was Not It, Today The Batty Was Dead Again, So I Charged It Back Up To 100% And took A Drew Test With A Test Light, The Light Was Lit With Nothing On, I Then Started Pulling Fuses ,, And Fuse # 21 Under The Hood Was Called Power Fuse And The Test Light Went Out, I Started The Car With Out The Fuse And It Set 2 Codes
This Was The Codes P1118 Manifold Absolute Temperature Circuit Low Input,, P1178 ( open )

So I Plugged In My Tester And Cleared The Codes That I Set In There.

I Also Replaced That Fan Belt But That Was After The Battery Was Going Dead, So Its Not The Belt I Know Its Tight Also I Went With The Toque Specks
Any Help On This Problem ??

I Did Buy The Extended 10 year 100 Thousand Mile Warranty 0 Deductable

Thanks For Any Help
Harley03joe

P. S. I'm An Auto Tech For O About 44 Years