F150 Battery Drain - Sometimes
Have been reading thru posts but have not seen this particular problem.
2005 F150 SuperCrew 2WD 5.4 Lariat- 98000 KM. Bought the truck 6 months ago and love it! Unfortunately a strange problem appeared the day after I bought it and persists to this day.
Problem: Truck will not start sometimes due to low battery. This only happens when I have unlocked the truck with remote or with keypad, then let truck sit for awhile (several hours) without starting the engine and/or not relocking it with remote or keypad.
Example - Yesterday, I unlocked the truck and vacuumed and washed the truck out at 10:30 am. I did not start the engine. Did not relock the truck when finished cleaning. At 4 pm, I jumped into the truck to make a run into town, turned the key and.... "click click click". Engine would not turn over, all dash lights go dim when attempting to start. Jump the truck with another vehicle, truck starts immediately. Make run into town and back. No further problems. Lock the truck using remote, let it sit overnight, unlock truck this morning with remote, truck starts as normal.
I have left the truck to sit for as many as 8 days and been able to start the engine without a problem. Truck was locked before I left it for that period.
What seems to be happening is that if the truck is unlocked with remote or keypad, it energizes something that puts a load on the battery. Unless the engine is started within a short time or the truck is locked again, there is a continuous drain on the battery until it doesn't have enough juice to start the engine.
I am not an expert but something tells me that there is some sort of relay that energizes a system or two that probably should do an "autoshutdown" of sorts if engine is not running and nothing happens within a short time.
When I close the door without locking the truck, the interior and cargo light does go out after a short delay. If I lock the truck with remote or keypad, interior and cargo lights turn off immediately.
I have not had an occassion to drive the truck, park it and forget to lock it so don't know if the same thing would happen in that circumstance (but I suspect it would).
Anyone else come across this problem? Any insight?