I Parked My Truck For 3 Days Without Starting It And The Battery Died.. I Have A Red Top Battery ($200) And A Brand New High Output Alternator So I Know Thats Not My Problem. My Buddy Told Me To Check For A Draw On The Batery By Removing The Negative Battery Cable And Putting A Test Light In Between The Negative Post On The Truck And The Negative Post On The Battery And If It Lights Up That Means There Is A Draw On The Battery.. Is This The Correct Way To Check??? Because It Did Light.. So I Am Wondering If He May Be Wrong And This Would Happen On Any Expedition, Or If He Is Right And This Means There Is A Draw On My Truck.. Any Help Would Be Appreciated Before I Start Ripping Out All My Fuses Tonight!!! Also I Thinl What Happened Was This.. My Rear Hatch Windows Actuator Is Going Bad.. Sometimes Ill Be Driving And The Door Ajar Light Comes On.. I Have Read The Threads And I Do See This Is A Usual Problem.. I Did Spray The Wd-40 But It Hasnt Seemed To Help.. (guess Ill Have To Spring For A New Latch) But I Am Thinking The Light Kept Going On And Killed My Battery, But Now Since I Listened To My Friend And Tried That Test Light Test I Am Afraid I Have A Draw On My Truck.. Can Anyone Here Maybe Try There Truck And Let Me Know.. Just Remove The Negative Cable And Put The Test Light Inbetween The Batterys Negative Terminal And The Trucks Negative Terminal.. See If The Test Light Illuminates... ?????

 

A test light can be misleading. Many will light with normal current draw on a modern vehicle. It's best to use an ammeter in series with the negative battery cable. Make sure the doors are closed and everything is turned off when testing. Your Excursion will keep many modules powered up for about 10-20 minutes after turning off the key, even after closing the door . Check the current draw after having the ammeter inline for 10-20 minutes with the key off. If you watch the meter, you will see when the various modules power down. The draw should be less than 25 milliamps (.025 Amps).
If the draw is more than that, start removing fuses until the draw drops to find the circuit with the draw. Common culprits are interior lights, voltage regulator, alternator, and any aftermarket items if installed. (Just because the alternator and battery are new, doesn't mean they can't be defective).