Help with voltage source at rear ?
Senior User
Joined: Feb 2011
Posts: 151
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On my 2017 the fuse was not installed from the factory for the wire that provides power to charge 5th wheel battery. Some dealers install them, some don't from what I read. The fuse is under the hood up front way back by the firewall. It is short and kind of hard to get to. It says the fuse number in the owners manual.
Mountain Pass
Joined: Feb 2007
Posts: 108
Likes: 1
On my 2017 the fuse was not installed from the factory for the wire that provides power to charge 5th wheel battery. Some dealers install them, some don't from what I read. The fuse is under the hood up front way back by the firewall. It is short and kind of hard to get to. It says the fuse number in the owners manual.
I have a loaded platinum and the relay for the tow charge is missing and can't be installed as even the pins that hold the relay are not present.
I have a feeling that there are two versions of these trucks, the ones with the factory brake controller use a tow management unit that is located in the drivers footwell that electronically controls relays in the tow management unit to turn on all of these functions.
Those trucks that do not come with a factory brake controller would be wired using the fuse box relay and fuse.
Senior User
Joined: Feb 2011
Posts: 151
Likes: 0
I can't speak for other configurations, just my own. 2017 Platinum Ultimate, crew cab, long bed 4x4 with the 6.7 and factory brake controller.
The fuse was in the engine bay, row of fuses closest to the firewall, somewhat in the middle of the row. Kind of a pain to get to. To figure out for sure I needed the fuse I took a fuse of the same rating, I want to say it was 30 amps from the anti-lock brakes possibly. Put it into the location I thought there should be a fuse, and I then had power to charge the trailer battery. I put the fuse back into where I got it and purchased a new fuse for the trailer power wire. Don't drop the fuse when trying to install or remove, you might not find it again. In some other post I also seen someone popped the plastic cover of the top of the fuse prying too hard, when removing one.
Before installing the fuse everything else as far as trailer lights and brakes worked fine, I just couldn't charge the battery.
The fuse I installed was similar to the link below, I cant say they were the exact same because I am going on memory. Some people might think it is a relay, when it is just a square fuse.
The fuse was in the engine bay, row of fuses closest to the firewall, somewhat in the middle of the row. Kind of a pain to get to. To figure out for sure I needed the fuse I took a fuse of the same rating, I want to say it was 30 amps from the anti-lock brakes possibly. Put it into the location I thought there should be a fuse, and I then had power to charge the trailer battery. I put the fuse back into where I got it and purchased a new fuse for the trailer power wire. Don't drop the fuse when trying to install or remove, you might not find it again. In some other post I also seen someone popped the plastic cover of the top of the fuse prying too hard, when removing one.
Before installing the fuse everything else as far as trailer lights and brakes worked fine, I just couldn't charge the battery.
The fuse I installed was similar to the link below, I cant say they were the exact same because I am going on memory. Some people might think it is a relay, when it is just a square fuse.
Many people are reporting that the fuse location may not be accurate.
I have a loaded platinum and the relay for the tow charge is missing and can't be installed as even the pins that hold the relay are not present.
I have a feeling that there are two versions of these trucks, the ones with the factory brake controller use a tow management unit that is located in the drivers footwell that electronically controls relays in the tow management unit to turn on all of these functions.
Those trucks that do not come with a factory brake controller would be wired using the fuse box relay and fuse.
I have a loaded platinum and the relay for the tow charge is missing and can't be installed as even the pins that hold the relay are not present.
I have a feeling that there are two versions of these trucks, the ones with the factory brake controller use a tow management unit that is located in the drivers footwell that electronically controls relays in the tow management unit to turn on all of these functions.
Those trucks that do not come with a factory brake controller would be wired using the fuse box relay and fuse.
Mountain Pass
Joined: Feb 2007
Posts: 108
Likes: 1
I can't speak for other configurations, just my own. 2017 Platinum Ultimate, crew cab, long bed 4x4 with the 6.7 and factory brake controller.
The fuse was in the engine bay, row of fuses closest to the firewall, somewhat in the middle of the row. Kind of a pain to get to. To figure out for sure I needed the fuse I took a fuse of the same rating, I want to say it was 30 amps from the anti-lock brakes possibly. Put it into the location I thought there should be a fuse, and I then had power to charge the trailer battery. I put the fuse back into where I got it and purchased a new fuse for the trailer power wire. Don't drop the fuse when trying to install or remove, you might not find it again. In some other post I also seen someone popped the plastic cover of the top of the fuse prying too hard, when removing one.
Before installing the fuse everything else as far as trailer lights and brakes worked fine, I just couldn't charge the battery.
The fuse I installed was similar to the link below, I cant say they were the exact same because I am going on memory. Some people might think it is a relay, when it is just a square fuse.
https://www.amazon.com/Profile-J-Cas.../dp/B00JLUWJ3G
The fuse was in the engine bay, row of fuses closest to the firewall, somewhat in the middle of the row. Kind of a pain to get to. To figure out for sure I needed the fuse I took a fuse of the same rating, I want to say it was 30 amps from the anti-lock brakes possibly. Put it into the location I thought there should be a fuse, and I then had power to charge the trailer battery. I put the fuse back into where I got it and purchased a new fuse for the trailer power wire. Don't drop the fuse when trying to install or remove, you might not find it again. In some other post I also seen someone popped the plastic cover of the top of the fuse prying too hard, when removing one.
Before installing the fuse everything else as far as trailer lights and brakes worked fine, I just couldn't charge the battery.
The fuse I installed was similar to the link below, I cant say they were the exact same because I am going on memory. Some people might think it is a relay, when it is just a square fuse.
https://www.amazon.com/Profile-J-Cas.../dp/B00JLUWJ3G
The charging circuit needs to see a trailer connected and it gets woken up by tapping the brake,
The Fuse you installed is not connected to anything in the fuse box, as the pins the fuse plugs into are missing, if you look for relay #37, you will find it missing and that is what the fuse you installed (#27) controls. IF you look at the position #37 where the relay should be, you will find the pins for the relay are actually missing.
IF you read the PDF I have attached, it has instructions within to make your Charging circuit always on, and it shows you the location of the trailer command module in the driver kick panel. Like I mentioned before, the charging circuit does not turn on unless you tap the brakes, and you have a trailer setup on your dash.
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