Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
Old 07-06-2022, 07:37 AM   #1
Junior Member
 
Join Date: Jul 2022
Posts: 3
F150 charging battery while towing

I have a 2018 F150 and would like to have 12v+ going to the battery while driving. What do I have to do?
Dealership says plug is working but it doesn't provide any juice.
Check the fuse and it's okay

Going to a different dealership but thought I would ask.
Lead dog is offline   Reply With Quote
Old 07-06-2022, 07:45 AM   #2
Part-Time Campground Host
 
cboss's Avatar
 
Join Date: Jul 2019
Location: Upstate NY
Posts: 3,179
Pin #4 is 12 vdc for charging, pin #1 is ground. With a multi meter check if you have 12 vdc (or so) on pin #4. If you do then the truck is providing 12 vdc to the camper unless there is a wiring issue from the camper plug to the battery
Also keep in mind charging your batteries with the truck 7 pin connector is not the most efficient. It's better to use your converter or a battery charger.
Attached Thumbnails
Click image for larger version

Name:	7-Way-RV-Style-Trailer-Plug-Wiring-Diagram-1.png
Views:	93
Size:	21.4 KB
ID:	276008  
__________________
Craig & Cath
2018 2902WS Rockwood Ultra Lite (with tons of Mods)
2022 F250 Lariat Super Cab, 7.3 gas w/10 Spd Xmsn
Equalizer Hitch w/4-Point Sway Control

Days camped since 2015(retirement): 1651
cboss is offline   Reply With Quote
Old 07-06-2022, 07:51 AM   #3
Site Team
 
Flybob's Avatar
 
Join Date: Oct 2014
Posts: 15,243
Some vehicles have a relay in the fuse block as well as the fuse. Also some vehicles only provide 12V on the Bargman connector when the ignition is on. The wire gauge used by the vehicle manufacturer is usually sufficient to keep a charged TT battery charged, but little more due to the resistance and length of the wire. If you need to charge the TT battery, you will most likely need to run a heavier gauge wire for the 12V pin.
__________________

2015 Freedom Express 248RBS
TV 2015 Silverado HD2500 Duramax
TST Tire Monitors
Honda 2000I + Companion
2 100W solar panels
Flybob is offline   Reply With Quote
Old 07-06-2022, 08:05 AM   #4
llr
Senior Member
 
Join Date: Feb 2017
Location: SW Ohio
Posts: 1,670
It also may not supply power it a trailer is not connected, measure the voltage at the trailer battery with and without the truck running. It should be noticeably higher with the truck running.
__________________
Almost not an SOB
Artic Fox 3018 5th Wheel - on order
Grand Design 2800BH TT 2021
Prior TT 2017 Flagstaff 831CLBSS Classic Ultra lite - SOLD 5/21
TV 2024 F350 DRW - on order
TV 2017 F150 6.5' bed 3.5 Eco-boost Max tow 1800lbs payload
llr is offline   Reply With Quote
Old 07-06-2022, 08:19 AM   #5
Junior Member
 
Join Date: Jul 2022
Posts: 3
Actually I connected the trailer, Started the truck, and put a meter at the battery on the tt and it didn't change. Vs when you do the same with a 250 it jumps to 14v.
Lead dog is offline   Reply With Quote
Old 07-06-2022, 08:29 AM   #6
llr
Senior Member
 
Join Date: Feb 2017
Location: SW Ohio
Posts: 1,670
Check the glove box and behind/under the seats to see if you can find a bad with some parts, at least one being a relay.

I am not sure is they still ship these un-installed but they used to
__________________
Almost not an SOB
Artic Fox 3018 5th Wheel - on order
Grand Design 2800BH TT 2021
Prior TT 2017 Flagstaff 831CLBSS Classic Ultra lite - SOLD 5/21
TV 2024 F350 DRW - on order
TV 2017 F150 6.5' bed 3.5 Eco-boost Max tow 1800lbs payload
llr is offline   Reply With Quote
Old 07-06-2022, 08:29 AM   #7
Senior Member
 
Chuck_S's Avatar
 
Join Date: Aug 2018
Location: Richmond VA
Posts: 4,510
Ford "trailer battery charge" connection is relay protected. Ignition must be On to get power there. (Sorry if I missed this.) There's also a fuze (and that relay) which I believe is under the hood -- at least on my Expeditions which are pretty close to the F150.

-- Chuck
__________________
2006 Roo 23SS behind a 2017 Ford Expedition
Chuck_S is offline   Reply With Quote
Old 07-06-2022, 08:33 AM   #8
Senior Member
 
Join Date: Jul 2017
Location: North of Seattle, WA
Posts: 17,263
Quote:
Originally Posted by Lead dog View Post
Actually I connected the trailer, Started the truck, and put a meter at the battery on the tt and it didn't change. Vs when you do the same with a 250 it jumps to 14v.
If the charging power is making it to the trailer's battery with a different truck the issue lies with the F-150 from the 7-pin connector to truck's battery where the 12v power originates. No need to chase the issue in the trailer.

Check fuse/fusible links at battery on truck.

As others have said, the power may only be present when a trailer is connected and sensed by the body control module through a relay.

Maybe this simple video will help:

__________________
"A wise man can change his mind. A fool never will." (Japanese Proverb)

"You only grow old when you run out of new things to do"

2018 Flagstaff Micro Lite 25BDS
2023 f-150 SCREW XLT 3.5 Ecoboost (The result of a $68,000 oil change)
TitanMike is offline   Reply With Quote
Old 07-06-2022, 08:38 AM   #9
Senior Member
 
Chuck_S's Avatar
 
Join Date: Aug 2018
Location: Richmond VA
Posts: 4,510
Simple relay to the ignition controls Ford trailer battery charge. No exotic sensing circuitry. But the ignition has to be On. This is there to prevent the trailer from draining the truck battery when parked -- some if not most GM trucks lack the relay and will kill the truck quickly when parked if there are large 12v draws in the trailer -- need I mention 12v refrigerators?

-- Chuck
__________________
2006 Roo 23SS behind a 2017 Ford Expedition
Chuck_S is offline   Reply With Quote
Old 07-06-2022, 04:22 PM   #10
New here, old elsewhere
 
lwbfl's Avatar
 
Join Date: Feb 2021
Posts: 287
Quote:
Originally Posted by cboss View Post
Also keep in mind charging your batteries with the truck 7 pin connector is not the most efficient. It's better to use your converter or a battery charger.
Unless the OP has a generator onboard, it would be hard to use either to charge the battery while driving
__________________
2021 Coachmen Apex Ultra Lite 253RLS
2016 Silverado 1500 Crew Cab Z71 / 6spd / 3.73
lwbfl is offline   Reply With Quote
Old 07-06-2022, 04:46 PM   #11
Senior Member
 
Join Date: Apr 2022
Location: Tarpon Springs FL
Posts: 3,280
connect volt meter to battery on trailer should read :

12.6 volts not connected to truck or when truck connected but not running



closer to 14v when truck running.... depending on your alternator you may have to increase revs


if the battery reads the same 12.6
make sure it is not turned off (isolated)


make same measurements at the truck

without trailer connected if the red charging wire not increasing to 13+ volts something wrong in the truck wiring / relay
if it is increasing to 13+v then the problem is in the wiring to the battery on the trailer
__________________
Tarpon Springs FL
2022 Salem 24RLXL
Aussieguy is offline   Reply With Quote
Old 07-06-2022, 05:19 PM   #12
Senior Member
 
Join Date: Jun 2016
Location: Mid Michigan
Posts: 1,098
Daughter and son-in-law's new trailer with 12 volt only frig would kill the trailer battery between home and campground. They asked the dealer about it and he looked in the fuse block under the hood and there was no trailer charge relay (F150). He installed one and all works now.
markb422 is offline   Reply With Quote
Old 07-06-2022, 05:25 PM   #13
Senior Member
 
Join Date: Sep 2009
Posts: 191
OP'er, did you by chance read the owners manual? It will have the answer for you but I suspect you will need a fuse and a relay. Good luck.
shadows4 is offline   Reply With Quote
Old 07-06-2022, 05:40 PM   #14
SJB
Member
 
Join Date: Jul 2019
Location: CO
Posts: 73
Quote:
Originally Posted by llr View Post
Check the glove box and behind/under the seats to see if you can find a bad with some parts, at least one being a relay.

I am not sure is they still ship these un-installed but they used to
Our 2013 F150 had the needed parts packed away in the glove box. A techie at WanaRV told us to look there
or we would never have found the needed parts. Once installed, the battery charged while we towed the trailer.
SJB is offline   Reply With Quote
Old 07-06-2022, 06:58 PM   #15
Junior Member
 
Join Date: Apr 2018
Posts: 18
My 2019 f150 does not send power to the trailer auxiliary power Unless the truck is in gear. You may consider rechecking the voltage at pin 4 with truck in neutral or if in gear with someone holding the brake.
rayham7777777 is offline   Reply With Quote
Old 07-06-2022, 07:12 PM   #16
Senior Member
 
Join Date: May 2022
Posts: 451
Our 2019 F-150 appears to be charging the battery. After long drives battery shows full, even with the 12v fridge running. Haven't checked to see if it was only while in gear. Don't remember having to do anything to make it work.
__________________
22 Freedom Express 257BHS
19 F-150 3.5 Max-Tow
fipntdot is offline   Reply With Quote
Old 07-06-2022, 08:25 PM   #17
Senior Member
 
Join Date: Nov 2019
Posts: 1,405
You didn't mention what trim level of F150 you have.

I have a '19 F150 Lariat which has a push button start. To get voltage here are the hoops needed.

Engine running, press brake pedal so the truck recognizes there is a trailer attached, leave the FOB inside the truck, fully close all doors on the truck. You'll see the 13.5V or so on the 12v pin. Skip any of the hoops listed above you'll have ZERO volts.

Hope this helps
__________________
2019 F150 4X4 7050 GVWR 1903 payload
2018 Avenger 21RBS 7700 GVWR
Mike134 is offline   Reply With Quote
Old 07-06-2022, 09:24 PM   #18
Senior Member
 
Join Date: May 2022
Posts: 451
Quote:
Originally Posted by Mike134 View Post
You didn't mention what trim level of F150 you have.

I have a '19 F150 Lariat which has a push button start. To get voltage here are the hoops needed.

Engine running, press brake pedal so the truck recognizes there is a trailer attached, leave the FOB inside the truck, fully close all doors on the truck. You'll see the 13.5V or so on the 12v pin. Skip any of the hoops listed above you'll have ZERO volts.

Hope this helps
Interesting. Ours is the 2019 XLT without the pushbutton start. The display acknowledges there is a trailer connected the moment you plug it in or if it is already plugged in when the truck is turned on. Now you got me wondering. it seems like our battery has been charging fine on several long trips. i suppose I will recheck the manual as well.
__________________
22 Freedom Express 257BHS
19 F-150 3.5 Max-Tow
fipntdot is offline   Reply With Quote
Old 07-07-2022, 09:11 AM   #19
Junior Member
 
Join Date: May 2020
Location: PA
Posts: 4
Dc to DC Charger

You might want to check out a dc to dc charger.
Check this:
Mickstir is offline   Reply With Quote
Old 07-11-2022, 08:55 PM   #20
Member
 
Join Date: Jan 2020
Posts: 11
I have a 2018 F150. Turn the lights from auto to on.

Forgot need truck running.
DLorenzen is offline   Reply With Quote
Reply

Tags
battery, charging, f150, tow, towing

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.



All times are GMT -5. The time now is 11:11 PM.