All Lights Work But Trailer Showing Not Connected on 2013 Ram 3500 with Factory Brake Controller

Question

Question:

On my 40foot 5th wheel trailer all turn signals, stop lights and tail lights work but on my dash when I set the amount of trailer braking I want I receive a dash warning, no trailer connected... which of course it is as the lights and blinkers work perfectly. I took the trailer to a rv shop today and they said when they hook their truck to my trailer the trailer brakes worked fine. So it must be with my truck somehow, fuse, relay, etc...??? Can you help?

asked by: Pat M

0

Expert Reply:

You're likely correct that this issue is with the truck, and I know that with the first generation of the factory integrated brake controllers on the Ram trucks there were a lot of issues like this that people have seen. You also mentioned that you changed the 7 way connector on your truck, so corrosion on the connection isn't going to come in play since it's new. I would start by checking the ground wire connections on the trailer and your vehicle's 7 way connection. You'll want to make sure that they are firmly connected to a paint and debris free surfaces.

If the ground wires are in good working order, I recommend checking the towing fuses on your truck to make sure that there isn't something blown on the trailer fuses (specifically the F11 fuse). Below you will find a list of the fuses that are related to the trailer connector on your 2013 Ram 3500.

F53 ATR 20 amp Left Trailer lights
F81 ATR 20 amp Right Trailer lights
F29 FFM 20 amp Trailer Park lights
F28 FFM 20 amp Trailer Back up lights
F30 FFM 30 amp Direct from battery
F11 J Case 30 amp Brake Lever
F87 ATR 10 amp ITBM module

The last thing I recommend looking at is on your vehicle's 7 way connector to make sure that power is being supplied to the brake wire when you press the brake pedal. If you're not getting power at the 7 way when the brakes are applied, it's likely that the issue is on this circuit; if you're not getting power you'll want to cut the blue brake wire on the factory brake controller and see if you're getting power at the back of the unit. If you're getting power from the unit there is an issue somewhere along the brake wire under the vehicle running to the 7 way connector.

If all of these check out and do not resolve your issues, please let me know and I can give you a couple of other spots to look.

expert reply by: Erik B

0

Markus

6/15/2024

I have a 2016 Ram 2500. I've been chasing multiple scenarios going down in a huge rabbit hole. I changed, brakes, plugs, wires and the internal brake controller. I have brakes and lights but still fighting with the trailer not connected. I need the option to choose the heavy brake option. The truck doesn't see a trailer connected so it will not allow to change settings.

Bud M.

6/15/2024

@Markus With having an internal brake controller you should check with your local Ram dealer to have the programming for the controller checked and updated. Since all the programming for this type of controller is through the trucks ECU I have seen occasions where the programming is messed up and causes all the issues.

Anthony

6/27/2024

@BudM so I just had my truck in the shop for this same exact issue. They recommended replacing the trailer brake module so I did. NOTE: if the truck come factory with a tow package you will not need it to be flashed. Fuse F30 check to see if if it’s blown this is where my problem is with my trailer breaks/ truck not recognizing a trailer is connected although all lights work. F30 fuse blew 3 fuses which tells me I have a wiring issue specifically with the trailer break / trailer connect feature. Best way to check this source is to pull the 4 pin plug from the break controller module, within that harness find the blue wire which is the trailer break wire which recognizes the trailer. If you put a multi meter on it turn ohm without pressing the breaks there should be zero continuity. If continuity is present then you have an open circuit on that wire. Spoke with dodge regarding this issue all they will do is inspect the wire to see if it’s grounding out somewhere replace that section and if they can’t find a cut ect within this wire they run a new wire from the 7 way plug to the blue wire into the module. Note if you don’t get continuity when testing then the problem consist within the wiring to the Tipm (fuse box).

Caleb

8/7/2026

i have an 08 ram 2500 and my brake controller does nothing. tried another controller and no change. all the lights on my trailer work as normal but not the brakes. i also get 12v constant to the 5 o’clock pin in the 7 way connector and 12v constant out of the blue brake wire on the controller even after cutting it. i need to put 7ton on this thing in a few days pls help

Heather A.

8/7/2026

@Caleb Hi Caleb, the constant 12 volts you’re seeing on the blue brake output wire is the first thing I’d chase down. Since you’ve already tried another brake controller and had the same problem, I’d check how the controller is wired into your 2008 Ram 2500, especially the red wire going to the brake light switch. That red wire needs to be connected to the cold side of the brake light switch, meaning it should only have 12 volt power when you press the brake pedal. If it was connected to the hot side by mistake, it would have constant power and could cause the controller to send power down the blue brake output when it shouldn’t. Grab your tester and check that red wire with your foot off the brake. You should have no power, then 12 volts when you press the pedal. If you have constant 12 volts there, you’ve found a good place to start. I’d also like to clarify one thing about the blue wire you cut. If you’re getting constant 12 volts from the blue wire coming directly out of the brake controller, I’d focus on that red brake switch connection first. If the constant 12 volts is actually on the other side of the cut, going back toward the truck’s 7 way, then we’re probably looking for a short or crossed circuit somewhere between the controller and the 7 way. With 7 tons behind you, I definitely want those trailer brakes working correctly before you head out. When you cut that blue wire, which side still had the constant 12 volts, the controller side or the side running back toward the 7 way?

All Lights Work But Trailer Showing Not Connected on 2013 Ram 3500 with Factory Brake Controller

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