Truck wouldnt crank the other day and had to be jumped off. Let it run for a while and then went back out a lil while later and I could barely get it cranked. Extremely low battery. This morning I couldnt get it cranked. Had battery tested it turned out good. They checked the alternator too and it checked out good. The wierd thing is that the running lights wont go off right now. Lights are in off position and key is obviously not in it. Any ideas as to what this is or whats causing it?

 

Let the truck run for almost 2 hrs. And still cant get enough charge in the batter this leads me to think the alternator. But the deal with the running lights is confusing me. Them staying on all night is prolly what drained the battery the first time... But that still doesnt explain that or why the battery wont hold a charge and crank now. Any info is greatly appreciated.

 

You can charge a battery all day but if its bad it wont hold a charge and it wont sustain a load. What method was used to check the battery? Also the lights staying on could be caused by low battery voltage confusing the bcm. Fix your battery issue then check your lighting issue.

 

If you have aftermarket remote starter unplug it. If you have DRL, system module may have a bad diode.

 

Ill check out the battery situation again. I had it checked at advance auto but that was after it had been running and hadnt had a chance to drain down I guess. I don't really trust those guys battery check methods they havent been very acurate in mine and friends experiences. Thanks for the input. Ill check back if i have any more issues.
Thanks

 

How old is the battery?

 

Also, what brand battery is it? We've had nothing but bad luck with any battery other than Motorcraft. (Haven't tried Optima, but we're sticking Motorcraft since there's been no issues) All of the battery's we've tried (Other than Motorcraft) have had issues like you're experiencing. Even when they're rated for the 650 CCA, they don't put out that much after a couple months.

 

One way to test the alternator is crank the truck and remove the battery cable. If the truck dies instantly you have a bad alternator if it keeps running it's good

 

Not sure how old the battery is. It was in the truck before I got it which is almost a year ago. And its an interstate. May try the alternator trick first and see if thats it. Thanks

 

Sounds like a bad battery to me. I haven't had good experiences with Interstate anyways, and I would reccomend a motorcraft.