Tow package fuse
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Junior Member
Joined: Apr 2019
Posts: 7
Tow package fuse
Hello,
I have a 2013 F-150 with a the towing package. I bought the truck with 37,000 mi January 2015. It has not given me any mechanic problems. We tow a travel trailer and the truck doesn’t charge the battery when we are on the road. It’s been a very hard time trying to get a answer from any ford Dealership. One sold me two fuses the position in the fuse box is #9 and #21. Number 9 is the trailer tow battery charger relay. Number 21 is the trailer tow battery charge relay power.
A couple of years ago one dealer sold me both but they didn’t bring DC power to the battery. The parts department seem to be making a calculated guess. Now that I have a new battery on the tow vehicle, I am trying again.
So if anyone knows what the correct part number is, I would appreciate that information.
Thanking all in advance,
Jim G
I have a 2013 F-150 with a the towing package. I bought the truck with 37,000 mi January 2015. It has not given me any mechanic problems. We tow a travel trailer and the truck doesn’t charge the battery when we are on the road. It’s been a very hard time trying to get a answer from any ford Dealership. One sold me two fuses the position in the fuse box is #9 and #21. Number 9 is the trailer tow battery charger relay. Number 21 is the trailer tow battery charge relay power.
A couple of years ago one dealer sold me both but they didn’t bring DC power to the battery. The parts department seem to be making a calculated guess. Now that I have a new battery on the tow vehicle, I am trying again.
So if anyone knows what the correct part number is, I would appreciate that information.
Thanking all in advance,
Jim G
Super Moderator
Joined: Jul 2006
Posts: 7,555
Welcome to the site Jim..
F21 is correct for the relay load feed IN. But you’ll also need F54 (5 amp) for switched/power distribution into the ‘coil side’ of the relay. The micro processor within the Body Control Module supplies the ground function for the coil side to then close the relays contacts to flow current. . If the fuses don’t activate the batt charge, let me know and we’ll dig deeper..
F21 is correct for the relay load feed IN. But you’ll also need F54 (5 amp) for switched/power distribution into the ‘coil side’ of the relay. The micro processor within the Body Control Module supplies the ground function for the coil side to then close the relays contacts to flow current. . If the fuses don’t activate the batt charge, let me know and we’ll dig deeper..
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Junior Member
Joined: Apr 2019
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Fuse 2013 F-150
Hayapower thank you for the welcome.
You have given me more info than the three dealerships that I stop at.
I checked #54 and it is in place. I am going to replace #9 this is the one a Ford service tech gave me from his tool box. He figured it was the one I needed. It maybe bad. Tuesday is my day to troubleshoot this and I will let you know how I make out.
What really ticks me off, both the parts man and service advisor didn’t have a clue. All they told me there was no way they could tell what fuse I need.
Thank you again I appreciate your help.
Jim
You have given me more info than the three dealerships that I stop at.
I checked #54 and it is in place. I am going to replace #9 this is the one a Ford service tech gave me from his tool box. He figured it was the one I needed. It maybe bad. Tuesday is my day to troubleshoot this and I will let you know how I make out.
What really ticks me off, both the parts man and service advisor didn’t have a clue. All they told me there was no way they could tell what fuse I need.
Thank you again I appreciate your help.
Jim
Super Moderator
Joined: Jul 2006
Posts: 7,555
F9 is for module interface for both Nav, GPS, and SYNC and a few other non related protections.
I don’t see how it would have any relation to the Batt charge.
When checking 21 and 54, if you have a 12v test light (or meter) make sure there is voltage present there, both sides of the fuse/s, not just a fuse in those positions (or visibly checking it’s not ‘open’). We need to know for sure ,, that fuse 21 is ‘Hot at all times’, and 54 is switched ON power meaning Hot in Run/Start’. If voltage is missing on either of those fuses as noted, could be a problem. If voltage is there following the Key positions,, then the BCM isn’t supplying the needed ground to close the relay, Or, the relay is failed..
If you have a test light and meter, (?) fairly easy to tell what’s missing at the relay connector.
I don’t see how it would have any relation to the Batt charge.
When checking 21 and 54, if you have a 12v test light (or meter) make sure there is voltage present there, both sides of the fuse/s, not just a fuse in those positions (or visibly checking it’s not ‘open’). We need to know for sure ,, that fuse 21 is ‘Hot at all times’, and 54 is switched ON power meaning Hot in Run/Start’. If voltage is missing on either of those fuses as noted, could be a problem. If voltage is there following the Key positions,, then the BCM isn’t supplying the needed ground to close the relay, Or, the relay is failed..
If you have a test light and meter, (?) fairly easy to tell what’s missing at the relay connector.
Last edited by Hayapower; Sep 21, 2019 at 05:28 PM.
Super Moderator
Joined: Jul 2006
Posts: 7,555
Odd,, looking up your trucks manual it does show #9 as relay protection,, schematics do not,. But the relay, like most any relay ,, only has or needs 2 power inputs to work. One, to supply current to the relay ‘Hot at all times’ (once the relay closes it feeds on through the relay to the batt charge at the trailer connector) and the other supply power input for the relays coil. So,, two power inputs, a ground added, bam you have power flowing out..
Ill double check #9,, but possibly it differentiates by VIN or model/equipment level etc..
Ill double check #9,, but possibly it differentiates by VIN or model/equipment level etc..
Super Moderator
Joined: Jul 2006
Posts: 7,555
7 pages of trailer light/charge circuit ops,, and none of them show a #9 fuse protection for the Batt Charge relay..
With that , the Owners Guide lists for ‘Power Distribution Box’ #9 = batt charge relay,, but technical shows the ‘Battery Junction Box’ with #9 but with no association related to the relay control/protection for BC.
Let is know what you find..
.
With that , the Owners Guide lists for ‘Power Distribution Box’ #9 = batt charge relay,, but technical shows the ‘Battery Junction Box’ with #9 but with no association related to the relay control/protection for BC.
Let is know what you find..
.
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Junior Member
Joined: Apr 2019
Posts: 7
2013 F-150 Tow battery
Well I am back again.
I replaced #21, it was blown. Tester shows hot all the time.
#9 was also replaced it has current on one side with key in the off position and current on both terminals in the on position.
#15 has current when key is in the on position.
With the truck running outlet, I checked all six terminals one shows current. My understanding is the center terminal is the one that charges the battery and that terminal does not have current.
Saying all that, I am lost.
I replaced #21, it was blown. Tester shows hot all the time.
#9 was also replaced it has current on one side with key in the off position and current on both terminals in the on position.
#15 has current when key is in the on position.
With the truck running outlet, I checked all six terminals one shows current. My understanding is the center terminal is the one that charges the battery and that terminal does not have current.
Saying all that, I am lost.
Super Moderator
Joined: Jul 2006
Posts: 7,555
No,, #7 center terminal is trailer back up lamps. #5 is trailer battery charge. If #7 was 'load attached' to your trailer battery, probably why 21 had blown. If #5 isn't hot, and the fuses remain good, make sure there's a relay plugged into the trailer tow battery position in the box..