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?

 

There've been several posts on this problem. I'm pretty sure the culprit is something called the "battery saver relay" that does as you suggest - powers everything down after a somewhat prolonged period (it seems to be about an hour in my truck). Until that happens, you still have a fairly heavy draw on the battery, even after the interior lights go out, and yes, it will drain your battery fairly fast.

This relay MAY require complete replacement of your fuse box. There's a guy using the sig "wreedKR" who had a similar problem and I'm pretty sure that's what the dealer did.

- Jack

 

Yes the dealer replaced my central junction box in the passenger kick panel because my battery would drain in a few days because the fuel pump relay was randomly energizing at times. The CJB is a $260 part and you must buy at the dealer. Unfortunately for us the fuel pump relay and battery saver relay are integrated in the box and cannot be replaced separately.


I would start with a battery test and a test of draw on the system.

How old is your battery?

 

Hi all, when I read the part in dmatkov's post
"
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."

My jaw dropped at the similarity to my problem ( I actually started thinking I had already and posted my problem earlier!)

I am the proud owner of a 2005 F150 King Ranch with approx. 94,000 Km on the clock. The morning after buying the truck I loaded up for a road trip but got no response when I turned the key, eventually got it jumped and once at the dealers they reported that the charging system seemed to check out fine and suggested that something may have been left on in the truck over night which drained the battery. My options were buy a new battery or just drive it and see if it held a charge. At that point I wrote it off to being so excited the previous evening that I had played with the toys too much or had inadvertently left a light switched on over night. I hit the open road and the problem seemed to go away. Recently I've found that if I don't drive the truck for a couple of days the engine doesn't seem to crank over as quickly and one morning last week I noticed the radio was tuned to the bottom of the AM frequency when I started up (no station there where I live). Yesterday I was once again unable to start the engine, getting only a couple of weaks cranks followed by the dreaded clicking sound. Could this be a battery at end of life or should I go after the dealer to check out the battery saver per wreedkr? I don't mind spending the money on a new battery (in fact I'd like to get a good one), I'd just hate to put one in a truck that is going to drain it right away.

 

I would test for draw on the electrical system FIRST fix if something found to be wrong, then replace the battery.

 

appreciate your quick reply. Any recommendations re: battery replacement?

 

I had a Optima but it failed or my fuse box ate it up. I would just go with a Diehard, nothing fancy.

 

Update on (apparent) Battery Drain
My apologies for not posting this earlier...

Shortly after posting the problem, I took a chance and bought a new heavy duty battery. Despite several occasions of letting the truck sit for over 6 straight days in very cold conditions this winter (-10 degrees celsius.... 14 degrees F), the engine turns over and starts immediately every time. Not a single problem since replacing the battery.

Don't know if replacing the battery was just a lucky guess or if there is still an underlying problem and the new battery has not yet been abused enough to give problems. Only time will tell... fingers crossed.

Still lovin' my truck!

 

I wonder if a weak battery aggravates the problem here? There are some components in electrical circuits that can increase demand on a battery if they sense a low voltage condition. Is it possible our trucks have components like these?

- Jack

 

This post got me thinking a bit. I just went through dealing with a dead battery issue on my new truck and, after weeks of issues, finally got the battery replaced.

What I noticed while I was experiencing the dead battery was that if I unlocked the truck with the remote, I would get a clicking sound similar to the door locks unlocking. It seemed like they kept trying to unlock, despite already being in the unlocked position. The only was to get the clicking to stop was to start the truck (which I had to do by jump starting it). Letting the truck run for a few minutes before shutting it off and locking the truck again, seemed to work okay. After experiencing this problem a few times I just started using the key to unlock the truck. No clicking this way. After the battery was replaced I've not experienced the problem at all.

My guess is similar to what some here have said: low battery voltage, combined with some of the components in the truck, seem to make the situation worse.

I'll certainly be keeping an eye on my battery to ensure that the problem is truly resolved.

 

I had the truck in for the brake booster hose recall and asked them to check things out while they had the truck in. They checked the battery and charging system and said everything looks good and that there isn't much else they can do unless I can get the truck to them while it is having the problem. This posses a bit of a problem since the issue seems (for now) fleeting and very intermittent. Is the battery saver relay supposed to protect the battery from all sources of excessive drain such as like leaving an interior light on or being plugged in to a TT that is drawing on the truck system? I am not guilty of either of those offenses but I'm trying to wrap my head around why the battery saver relay didn't come up as the next logical thing to check when they had the truck in.

 

Shortly after my original post, I took a chance and replaced the battery with a new heavy duty battery. Have not had a single problem since, going on two years now. Apologies for not following up soon after installing new battery to update you all.

Last two summers I've been hauling around a 7000# race trailer or a 30 foot travel trailer almost every other weekend. The truck hasn't given me so much as a hiccup. Now have 135000 KM on the truck and still lovin' it!

Have recently installed new tires, MagnaFlow SIDO exhaust and an Edge Evo programmer. Will be installing a K&N CIA when it arrives. Already noticed roughly 10% better gas milage with Edge programmer in tow mode.

 

The fact that you updated the issue is greatly appreciated by the next member that has similar symptoms. Add to that you have long term confirmed testing of the solution, that part I have never seen.

Thanks for updating your thread with the confirmed solution.

 

I had the same on my 2006 and just replaced battery and alt. Though all was good but just started again. If I don't start at least once a day, then it wont start at all untill I boost or charge. I think getting the new battery just meant that it would take longer to drain. It didn't actually fix the prob. A quick ammeter check shows about a 5 amp drain. I had planned on pulling each fues/circuit breaker and see which circuit has the 5 amp draw.
With the battery saver circuit, what activates it? Using Remote to lock or unlock, start vehicle or not? And where is it located on my 4.7 ltr 4x2 2006?

 

This is a Ford forum, not a Dodge forum........