Power Draw

[BSouders80]

I've got something drawing power on my 2014 Raptor. About 10 days ago, battery was dead. Alternator is charging good. I thought maybe it was just the battery.... Battery was 6 months old, and I swapped it for a new on on Saturday.

No issues since then. This morning though, battery was dead dead. No lights, nothing. I jumped it to get it started. Voltage kicked up to 13.8 volts. Drove for 15 minutes and battery was charged enough to re-start with no issues. So evidently I have something drawing power. Lights are set in auto, so they turn off automatically. I have a radar detector, but that should not draw a battery in 12 hours.

Any suggestions on how to trace this down or where to maybe start?

Electrically, I replaced the fuse for the trailer brakes so that I could pull a car trailer over the weekend. The trailer lights and brakes worked good when pulling. I had to rewire the plug on the trailer and replace the fuse for the trailer brakes, but that is all that I did on that effort.

 

[Jakenbake]

I think the preferred method is to hook up a multimeter to the battery posts to confirm there is a draw. Then you can pull fuses one at a time to see when the draw stops. That would determine the circuit with the issue(s).

Could also start by eliminating the fuse panel under the hood vs the floor board mounted one. Save you from pulling 50% of fuses. If you have added fuses for other items you would have to check those as well.

I have not personally done this, so I may have left out a step, but this is where I would start. Think it through and modify as necessary sort of thing.

 

[BSouders80]

Good point about pulling fuses to see which circuit is drawing power. With the key out of the ignition, should there be any power drain?

Let's say I remove the leads from the battery and let's say i get 12.00 volts. With the leads installed on a truck where there is no power draw going on, should I still get 12.00 volts or would I expect to see a little less on voltage with leads hooked up? Example on keeping memory on radio, seat settings, etc. With a power draw, any idea on how much of a decrease I should see vs no power draw?

 

[Jakenbake]

@FordTechOne would be a good resource on what is acceptable draw.

As far as the meter goes, I would think you would want to monitor current rather than voltage.

 

[BSouders80]

I can look at amperage or voltage and should be able to use either value. Hopefully @FordTechOne will chime in. I suspect I'll start with checking that fuse that I replaced for the trailer brakes.

 

[FordTechOne]

To check battery draw, install a multimeter in series between the negative battery terminal and negative battery cable. The maximum allowable amperage draw is 50 milliamps/0.05 Amps after the truck has gone to “sleep”, which takes approximately 20 to 45 minutes. Try not to break the connection when installing the multimeter, otherwise you’ll need to start over to allow the modules to go back to “sleep”.

One of the most common parasitic draws on this generation of F-150 is a faulty Park detect switch, which is part of the shifter assembly. If the “P” in the instrument cluster doesn’t light up when the shifter is placed in park, you most likely have a failed park detect switch.

 

[BSouders80]

My raptor was dead dead when I came out to leave from work. I jumped it and it started fine. When I looked at the display on the sct programmer, it showed the voltage to be right around 12.2 volts. When the fans kicked off, voltage went up to 13.5 to 13.8 volts. So I took it in to O'Reilly's to see if they could test the alternator. Their test showed that the voltage regulator failed. Diodes passed and sitting there with the fans on, it showed 13.4v on their test screen. From time jumped to when I got back to the house was around an hour of run time on the alternator. Voltage at the battery check to be 12.87v after shutting off.

I have a $75 multimeter from O'Reilly's. It does do milliamps. @FordTechOne Can you elaborate a little more on the draw test? I'm not clear on the "try not to break the connection when instsalling the multimeter."

Wouldn't I need to disconnect my negative terminal to measure the amp draw or are you saying to have probe one on the post and one clipped to the terminal as I unhook the cable after 45 mins? That's kind of how I take it, but any extra info would be appreciated.

 

[BSouders80]

I changed my meter to 10 amp draw and it's pulling 3.45 amps currently. I'll wait another 30 mins and see what it bottoms out at. Then start pulling fuses.

 

[BSouders80]

@FordTechOne @Jakenbake
I figured out the amp draw with the multimeter. How many amps will the circuit pull until the modules go to sleep?

The fuse box under the hood, that's not bad. Have the multimeter there by me and pull fuses and watch for any decrease in amp draw. Under the hood, I pulled every fuse and the black plugs (modules?) No change. There is a LED light hooked to the same post as the battery terminal is hooked to. Pulled that and no change.

The fuse box inside the passenger trim area..... I have to pull those fuses with the door open to get to those. I pulled a vertical row, shut the door, wait 20 minutes and I can't get below 3.15 amps. There are about 10 fuses in that box that I gave up on for the night. I can get back after it tomorrow night. On those fuses though, with me opening the door, pull half a dozen fuses, close the door, are the modules no longer in "sleep" mode? Is there a more efficient way to pull the ones on passenger trim?

I would pull half a dozen fuses, shut the door, wait 20 minutes and then check amp draw. I never got it below 3.15 amps.

On the gear selector, it shows P park on the shifter when in park, shows P on the dash when in park.

For now, I just disconnected the negative and put the 2 amp charger on it for the night.

Again - O'Reilly was trying to tell me that my alternator is bad. It showed that the voltage regulator failed, but diodes were good. Truck was dead dead after work. Jumped it, drove it for probably 40 mins, idle for 20 mins. Battery charged quite well. Showed 12.87 volts when I checked voltage of battery before pulling fuses and checking amp draw.

Thoughts? Suggestions?

 

[Jakenbake]

@FordTechOne @Jakenbake
I figured out the amp draw with the multimeter. How many amps will the circuit pull until the modules go to sleep?

The fuse box under the hood, that's not bad. Have the multimeter there by me and pull fuses and watch for any decrease in amp draw. Under the hood, I pulled every fuse and the black plugs (modules?) No change. There is a LED light hooked to the same post as the battery terminal is hooked to. Pulled that and no change.

The fuse box inside the passenger trim area..... I have to pull those fuses with the door open to get to those. I pulled a vertical row, shut the door, wait 20 minutes and I can't get below 3.15 amps. There are about 10 fuses in that box that I gave up on for the night. I can get back after it tomorrow night. On those fuses though, with me opening the door, pull half a dozen fuses, close the door, are the modules no longer in "sleep" mode? Is there a more efficient way to pull the ones on passenger trim?

I would pull half a dozen fuses, shut the door, wait 20 minutes and then check amp draw. I never got it below 3.15 amps.

On the gear selector, it shows P park on the shifter when in park, shows P on the dash when in park.

For now, I just disconnected the negative and put the 2 amp charger on it for the night.

Again - O'Reilly was trying to tell me that my alternator is bad. It showed that the voltage regulator failed, but diodes were good. Truck was dead dead after work. Jumped it, drove it for probably 40 mins, idle for 20 mins. Battery charged quite well. Showed 12.87 volts when I checked voltage of battery before pulling fuses and checking amp draw.

Thoughts? Suggestions?

As far as the ones inside the cab. Open the door and let it set for a while. When you go in to pull a fuse, just do not close it again. You can almost close it and it shouldn’t trigger then sensor again.

I sorta do that when I working on anything in the interior that might take a while. Pull it in the the garage and open all 4 doors and do not close them all the way after that.