Power to trailer

[ccampbell0782]

Is there a trick when plugging in the trailer to the 7 way on the truck to have 12v power sent to the trailer? (not for marker lights). My past trucks is just plug in and all set, but this truck isn't sending 12v power.

 

[GATORB8]

On past trucks, the fuse for the 7 Way constant was included in the packet with the harness for aftermarket brake controllers.

May want to check and see if it's left out.

Internal Power Distribution Center
The Power Distribution Center is located under the drivers side instrument panel. This center contains cartridge fuses, micro fuses, relays, and circuit breakers. A description of each fuse and component may be stamped on the inside cover, otherwise the cavity number of each fuse is stamped on the inside cover that corresponds to the following chart.

Cavity/Cartridge Fuse/Micro Fuse/Description
F01/30 Amp Pink/–/Trailer Tow Receptacle
F25/40 Amp Green/–/Mod Integrated Trailer Brake

 

[RamCares]

Is there a trick when plugging in the trailer to the 7 way on the truck to have 12v power sent to the trailer? (not for marker lights). My past trucks is just plug in and all set, but this truck isn't sending 12v power.

Hello ccampbell0782,

Please check the voltage at the truck’s 7 way with a volt meter to confirm if the pin is providing power. Please let us know the results.

Thank you

Lamar
RAM Social Care Specialist

 

[1stRamowner]

Hello ccampbell0782,

Please check the voltage at the truck’s 7 way with a volt meter to confirm if the pin is providing power. Please let us know the results.

Thank you

Lamar
RAM Social Care Specialist

Hate to jump on an old thread but I just bought a 2019 1500 and I have no power at the 4 pin or 7 pin receptacle for the trailer running lights, I checked the fuse and it is good (confirmed with ohmmeter). All the other functions work left turn, right turn, brake, brake controller and 12v all work as should just no power for the running lights. I owned a dakota years ago that I had to install a couple relays to get all of the trailer functions to work properly is this the case with this truck also?

 

[riccnick]

The park light circuit is for the "running lights" on trailers, there should be a dedicated fuse for trailer park lights. Let me see if I can dig up some more info on it.

 

[riccnick]

Here's what I found, right in the owners manual.

 

[1stRamowner]

Yeah that is the info I have as well looked it up in the owners manual and the back of the fuse cover, as I stated all fuses are good but still no power to the rear of the truck for the running lights. As of right now I need to take it to the dealer, just hoping to find some simple (possibly) known problem. Thanks!

 

[Jus Cruisin]

Make sure the pins in the trailer plug match the 7 pin truck. You might have to move them to match the truck. I've had to do that a couple of trailers ago.

 

[riccnick]

Make sure the pins in the trailer plug match the 7 pin truck. You might have to move them to match the truck. I've had to do that a couple of trailers ago.

Good point, I also had to do this for one trailer we bought

 

[RamCares]

Yeah that is the info I have as well looked it up in the owners manual and the back of the fuse cover, as I stated all fuses are good but still no power to the rear of the truck for the running lights. As of right now I need to take it to the dealer, just hoping to find some simple (possibly) known problem. Thanks!

Hi 1stRamowner,
Let us know how your appointment goes! We're available via private message if you need any additional assistance.
Lydia
Ram Social Care Specialist

 

[1stRamowner]

So it turns out I was not crazy there was a broken wire on the harness going back to the trailer plugs the dealership repaired it and hopefully all is well

 

[Patsy1099]

So it turns out I was not crazy there was a broken wire on the harness going back to the trailer plugs the dealership repaired it and hopefully all is well

Thanks for posting the resolution. Hope it’s working now

 

[varmintjcl]

I know this is a very old thread, but I recently had the same issue and replaced the 30amp F01 in the internal fuse panel and it didn't help, so I took it to the dealer who charged $75.00 to replace a fuse but they couldn't tell me which fuse they replaced!
would it be the 20amp F12 under the hood? I really need to know in case I'm out late on a lake and need these lights working to get home!

 

[GATORB8]

I know this is a very old thread, but I recently had the same issue and replaced the 30amp F01 in the internal fuse panel and it didn't help, so I took it to the dealer who charged $75.00 to replace a fuse but they couldn't tell me which fuse they replaced!
would it be the 20amp F12 under the hood? I really need to know in case I'm out late on a lake and need these lights working to get home!

Looks like it for the running lights. Pull it and see if it stops the lights.

 

[tyromeo55]

I know this is a very old thread, but I recently had the same issue and replaced the 30amp F01 in the internal fuse panel and it didn't help, so I took it to the dealer who charged $75.00 to replace a fuse but they couldn't tell me which fuse they replaced!
would it be the 20amp F12 under the hood? I really need to know in case I'm out late on a lake and need these lights working to get home!

Had my electric/HYD tilt trailer running lights go out and the fix was replacing f12 under the hood. It seems that a lot of manufacturers put the trailer pump battery on the running light circuit for charging the battery while you go down the road (as long as you have them turned on). If that battery is really low or you bump the motor while on it will overwhelm the circuit and pop that fuse. In a pinch I pulled f8 and used it to get me we’re I needed to go (trailer backup Lts).
Side note. Those cartridge fuses are hard to tell visually if blown. Only real way to tell for sure is to test

 

[sand2snow]

Glad I found this thread. 2019 Ram Limited is shop truck. Electric over hydraulic brakes not working on selected boat trailers that have them. After using this tool we determined we weren't getting 12V on the 12V pin at the 1 o'clock location. We could plug this tool into other trucks even with the trucks off and get the 12v light to light up:

Amazon.com

Did not know about the other fuse panel located behind the panel near drivers knees. Sure enough F01, 30Amp was blown. New fuse and problem solved.

 

[sand2snow]

This is also a great tool to test trailer lights:

IPA Light Ranger MUTT RV and Utility-Type Trailer Light Tester Model# 9101 | Northern Tool

The IPA® Light Ranger MUTT® RV and Utility-Type Trailer Tester reduces guesswork and saves time by powering each trailer ...

www.northerntool.com

 

[Georgf]

I'll pick up old thread, I have the same problem: no power at the 7pin connector on running lights or trailer backup. Works only battery +12v and stop/turn contacts. All fuses are intact, in underhood or internal power distribution box. It’s first time i use the trailer connector, did someone solve this problem without dealership?

 

[tyromeo55]

I'll pick up old thread, I have the same problem: no power at the 7pin connector on running lights or trailer backup. Works only battery +12v and stop/turn contacts. All fuses are intact, in underhood or internal power distribution box. It’s first time i use the trailer connector, did someone solve this problem without dealership?

From memory so you might take what I'm saying with a grain of salt.
Trailer running lights are fed from an under hood 20A MCASE style fuse. I have a tilt equipment trailer that is driven by a double acting hydraulic pump. Learned quickly that the trailer battery is wired in parallel with the running lights. If I engage the hydraulic motor with running gear lit up it will pop that fuse so I keep spares. One day I might install a DC-DC charger but it hasn't been a big enough issue to warrant spending the time or $$