03 f150 5.4

[tcward]

A couple of weeks ago I went to start my truck temp outside was about 25 and it was dead as a stone. I jumped it off and drove it about 50 miles that day with no further problems. The next day it cranked but was sluggish. Last Monday morning went to start it and stone dead again! So..not really knowing the age of the battery, I put in a new one. Yesterday morning stone dead again! Jumped it off once more and has cranked fine 2-3 times since. I did check voltage with engine running and meter said 14.4 volts. I shut off the engine and battery read 12.6 volts. Just checked battery a little while ago and it read 12. 4 (about a 3 hour wait since previous check). One thing to note is this truck usually sits 3-5 days between uses. So any ideas what is going on? Thanks in advance for any help!

 

[NE GA Pappy]

something is a parasitic draw on the battery. the 12.6 12.4 doesn't bother me as much as the not cranking after 4 or 5 days. Put a amprobe on a meter and go to checking fuses to see which circuit is pulling the power all the time.

Trial and error type diagnosis.

 

[Wycliff]

May be a simple fix as the light on in the glovebox, had this happen with a jeep I have

 

[GoldDot40]

something is a parasitic draw on the battery. the 12.6 12.4 doesn't bother me as much as the not cranking after 4 or 5 days. Put a amprobe on a meter and go to checking fuses to see which circuit is pulling the power all the time.

Trial and error type diagnosis.

Agreed...parasitic draw is suspect. The equipment they use at Advance Auto Parts can actually detect a parasitic draw. It won't pinpoint it, but it can pretty much confirm if one is present. The good part about it...is that it's a free test and will just cost you a few minutes of your time. Make sure you explain what you're looking for. They will test the battery and charging system...the parasitic draw detection is a by-product of the test.

 

[NE GA Pappy]

May be a simple fix as the light on in the glovebox, had this happen with a jeep I have

I had a Ford van once that the brake pedal would stick just enough to leave the brake lights on. You wouldn't notice in the daylight, and by nightfall it was so dim you couldn't see it.

I have also seen the under the hood light stay on all the time and do the same thing.

 

[tcward]

Thanks guys. Gonna try the fuse check to see what it turns up. Checked all interior and interior lights after dark to make sure nothing was on.

 

[tcward]

Also going by Advance to see what they say.

 

[chadf]

Volt meter can easily check, each side of a fuse, in each(u have more than one fuse>) fuse block of the vehicle

$3 test light(harbor freight,etc) will do the same
Check for good ground with test light

 

[NE GA Pappy]

Volt meter can easily check, each side of a fuse, in each(u have more than one fuse>) fuse block of the vehicle

$3 test light(harbor freight,etc) will do the same
Check for good ground with test light

if he grounds the test meter, and then touches one side of the fuse and then then other, it will only tell him if the fuse is good, not if the circuit is pulling juice. You have to have an amprobe to check for amp draw on the fuse to determine if it is drawing.


And of course, it could always be a bad battery that he got. I know it is a long shot, but I have seen batteries have shorted cells right off the bat like that.

 

[GA native]

You have a short to ground somewhere.

The way I test is to disconnect the negative cable from the battery. I complete that (neg cable to battery) circuit with my voltmeter, set to DC. Then I open the fuse box, and pull one fuse at a time. When the meter goes to zero volts, you found the grounded circuit.

Finding the bad circuit is the easy part.

 

[rospaw]

You have a short to ground somewhere.

The way I test is to disconnect the negative cable from the battery. I complete that (neg cable to battery) circuit with my voltmeter, set to DC. Then I open the fuse box, and pull one fuse at a time. When the meter goes to zero volts, you found the grounded circuit.

Finding the bad circuit is the easy part.

This

Just last week had the same problem on a ford excursion with a V10. Truck would not start. Would start with jumper box. Charged battery twice over night with no luck. Battery checked good. Ended up being the ground cable about 4" from the terminal where a smaller (8 gage) ground slices in with the main ground cable. Cut both off and replace with new batt terminal. Just enough length to make it reach the neg batt terminal.

 

[tcward]

Update..the truck has been sitting since Sunday afternoon. Tried to crank it this afternoon and it fired right up with no hesitation! The only things I did Sunday before leaving it was to reposition battery cables on post and tighten securely and turn off the radio (clock stays on normally.) Do you guys think either could have caused the problem?

 

[NE GA Pappy]

radio is a common failure with parasitic drain

 

[NE GA Pappy]

You have a short to ground somewhere.

The way I test is to disconnect the negative cable from the battery. I complete that (neg cable to battery) circuit with my voltmeter, set to DC. Then I open the fuse box, and pull one fuse at a time. When the meter goes to zero volts, you found the grounded circuit.

Finding the bad circuit is the easy part.

doesn't work on some of the newer stuff because of computers drawing constantly and monitoring things like remote start.

 

[GA native]

doesn't work on some of the newer stuff because of computers drawing constantly and monitoring things like remote start.

You're right. My 85 Yamaha dropped to zero when I found my ground fault.

On newer cars, the meter won't drop to zero, but the draw will drop considerably when you pull the circuit with the ground fault.

A car should be able to sit a few months and keep enough juice in the battery to start it. All of that peripheral gee gaw draws milliamps. Any draw more than 20 or so milliamps will be your ground fault or parasitic drain.

 

[rospaw]

Update..the truck has been sitting since Sunday afternoon. Tried to crank it this afternoon and it fired right up with no hesitation! The only things I did Sunday before leaving it was to reposition battery cables on post and tighten securely and turn off the radio (clock stays on normally.) Do you guys think either could have caused the problem?

I think you just made a temporary connection by moving the cables. Any greenish corrosion on the neg cable even at the splice?

 

[NE GA Pappy]

You're right. My 85 Yamaha dropped to zero when I found my ground fault.

On newer cars, the meter won't drop to zero, but the draw will drop considerably when you pull the circuit with the ground fault.

A car should be able to sit a few months and keep enough juice in the battery to start it. All of that peripheral gee gaw draws milliamps. Any draw more than 20 or so milliamps will be your ground fault or parasitic drain.

yes, but I thought you said to set the meter on DC volts. Even if he was only drawing 5 milliamps, it would still show a 12v circuit and never drop to zero volts, That is why I said earlier that he needed an amprobe

 

[tcward]

radio is a common failure with parasitic drain

If the radio is the problem, what do you do Pappy, replace the unit, fuse or what?

 

[tcward]

Update on the situation. The very next morning after my last post, the truck would not crank. So I took it to the shop. Turns out I had a parasitic draw through the battery saver relay. Replaced that and so far so good.