2025 Ram Trailer Light Issue

[Canojams]

So I just went through this issue with the service department. The truck has the full tow package. I brought the trailer along as requested by the technician. The trailer s drawing 7.5 amps. (As designed). They said the truck's computer is designed to 3.5 amps and claimed the truck has a short. The dash display says to check connection and check for lamp out on trailer. They charged me $199.00 diagnostic charge. After I left I went to tractor supply and bought an incandescent trailer light kit. It worked fine. I owned my trailer 20 years and never had an issue. It has 16 running lights that draw 1/2 amp each.

 

[Canojams]

Correction they said the trailer has a short not the truck.

 

[Dean2]

So I just went through this issue with the service department. The truck has the full tow package. I brought the trailer along as requested by the technician. The trailer s drawing 7.5 amps. (As designed). They said the truck's computer is designed to 3.5 amps and claimed the truck has a short. The dash display says to check connection and check for lamp out on trailer. They charged me $199.00 diagnostic charge. After I left I went to tractor supply and bought an incandescent trailer light kit. It worked fine. I owned my trailer 20 years and never had an issue. It has 16 running lights that draw 1/2 amp each.

Did you mean an LED light system, or did you really get a new incandescent system that solved the problem with your old incandescent trailer light package. Not busting your chops, just want to make sure I understand. The fact ypur pickup only puts out 3.5 amps tells me it is designed for LED.

 

[Canojams]

No, I bought the incandescent boat trailer type kit just to see if they worked. They are rated for 3.5 amps total for each fixture( left and right including brake and turn signal). I wired them per directions and plugged them into the truck. Everything worked fine. I think RAM should buy me a new trailer that's compatible with their trucks.

 

[Canojams]

I should say the 2025 RAM witj the 3.0 Hurricane engine is only rated for 3.5 amps for rumning/ tail lights. I' pretty sure their 2024 trucks with the HEMI would work

 

[Canojams]

So here is the report they gave me. I don't know how the truck can distinguish left or right tow lamp circuitry if the tail/ running lights power supply is only 1 wire that is either on or off. It's independent of the turn and brake lights.

 

[Gunny7156]

I am having the exact same issues. Traded 2023 Ram 2500 Rebel with 6.4 to new 2025 2500 Cummins. Same boat trailer for boat, 2020 shore lander with factory installed LED lights. Normal process when hooking up boat/trailer to tow is back truck up to trailer, connect hitch, safety chains, and lastly install 7pin into outlet. Then I turn headlights on to verify my lights are working...Old truck, check, all working, proceed to go fishing. New truck...same process, truck in not recognizing trailer through lighting. no headlight setting works. Turn truck off, unplug 7pin, reinstall 7pin, turn truck on, go through headlights and maybe it'll work, maybe it won't. Been times I've had to stop/restart truck and turn headlights 8-10 times but if and when they finally come one, I'm getting pulsating lights on LED trailer lights. Twice so for this has happened that I'll go fishing, launch the boat, trailer is still connected to truck, 7pin is connected. Come back couple hours later when done fishing, retrieve truck to put boat back on and bingo, lights work as should, no pulsating. Couple days later, want go fishing, back to square one, start/restart truck to get lights to work, pulsating trailer lights when they do come on. Go fishing, come back, restart truck while everything is connected and works perfect. On 8/4/25, had truck at ram dealer along with my boat/trailer and they reflashed the ECM. Said wait 24 hours and go to go. 24 hours later, connect boat trailer and NOPE back to same BS, start/restart and pulsating lights. Back to dealer on 8/11/25 for round 2. Also son has 2023 Ram Power wagon and no issues with his truck and my trailer just like my 2023 Rebel I traded in. NO, it's not a trailer issue, 100% truck issue. Yes, Ram Care is involved but Ram Care is a joke and useless. Not exaggerating, I've called them 15-20 times this week and still don't know if I have an open or closed case because of the conflicting crap they are giving me. Case manager says yes it's open, "7eleven" rep tells me case is closed and can't do anything until I go back to dealer on 8/11/25.

 

[Art Vandelay]

I am having the exact same issues. Traded 2023 Ram 2500 Rebel with 6.4 to new 2025 2500 Cummins. Same boat trailer for boat, 2020 shore lander with factory installed LED lights. Normal process when hooking up boat/trailer to tow is back truck up to trailer, connect hitch, safety chains, and lastly install 7pin into outlet. Then I turn headlights on to verify my lights are working...Old truck, check, all working, proceed to go fishing. New truck...same process, truck in not recognizing trailer through lighting. no headlight setting works. Turn truck off, unplug 7pin, reinstall 7pin, turn truck on, go through headlights and maybe it'll work, maybe it won't. Been times I've had to stop/restart truck and turn headlights 8-10 times but if and when they finally come one, I'm getting pulsating lights on LED trailer lights. Twice so for this has happened that I'll go fishing, launch the boat, trailer is still connected to truck, 7pin is connected. Come back couple hours later when done fishing, retrieve truck to put boat back on and bingo, lights work as should, no pulsating. Couple days later, want go fishing, back to square one, start/restart truck to get lights to work, pulsating trailer lights when they do come on. Go fishing, come back, restart truck while everything is connected and works perfect. On 8/4/25, had truck at ram dealer along with my boat/trailer and they reflashed the ECM. Said wait 24 hours and go to go. 24 hours later, connect boat trailer and NOPE back to same BS, start/restart and pulsating lights. Back to dealer on 8/11/25 for round 2. Also son has 2023 Ram Power wagon and no issues with his truck and my trailer just like my 2023 Rebel I traded in. NO, it's not a trailer issue, 100% truck issue. Yes, Ram Care is involved but Ram Care is a joke and useless. Not exaggerating, I've called them 15-20 times this week and still don't know if I have an open or closed case because of the conflicting crap they are giving me. Case manager says yes it's open, "7eleven" rep tells me case is closed and can't do anything until I go back to dealer on 8/11/25.

I have had my 2025 Ram 1500 for about 2 months. I just moved my TT to get ready for my trip to UT and AZ. Checked lights and the running LED lights cycle on/off. Plugged a tester in and it shows no issues. Called two family members and they were both out with a 2010 Ram and a 2021 Explorer. Both stopped by and the trailer has no issues with either vehicle. The trailer had no issue with my 2014 Grand Cherokee two months ago before it was traded. I'm seeing that the system is light weight. No doubt that todays trucks are 400hp-500hp to drive across pavement to get groceries. I'm wondering that if the batteries being not fully charged and the converter is drawing, if this would be an issue with draw from the truck. Wondering if the system can easily be upgraded to where trucks were before children designed them on laptops in Detroit. Does your boat trailer have an extra draw from some battery maintainer or charger?

 

[crash68]

I'm wondering that if the batteries being not fully charged and the converter is drawing, if this would be an issue with draw from the truck.

It most likely has to do with how they're switching the trailer lights on/off. Previous generations used plain old relays, now they use some form of transistor. It's not really a problem with the transistors but thow they use them in the circuit to determine if the trailer lights work.
If you put load resistors on the trailer lights the problem should go away. Probably can use 10 or 12 Ohm resistors on the three trailer lighting circuits. There shouldn't be any issue with using the trailer on other vehicles as the resistors act like extra lights.

 

[Gunny7156]

Service appointment #2 yesterday (8/11/25). This occurred one other time before when I towed the boat. Launched boat, came back 3-4 hours later, started truck and BINGO!, trailer lights worked fine. Hooked boat up Sunday night before yesterday's appointment. Started truck with boat and trailer already plugged in from night before. Again, worked perfectly....drove to dealer with boat and trailer. Showed technician lights worked perfect as I left it running until he observed. Shut truck off, unplugged 7pin to truck, reinserted 7pin, restarted truck and back to pulsating lights. 3 hours later with a conference call with the STAR engineers determined the issue is the integrated trailer control module. Kinda strange that's what I told the tech my last appointment on 8/4 that was the known issue with some many guys on forums and Facebook. But they insisted that step 1 is to reflash ECM to "fix" the issue (which didn't) then onto next step with engineers. Another kick in the pants that the ITCM is on backorder and trip #3 to dealer in near future since they had to order one. I'm quite confused as to the process and how to run a business. Take a vehicle in for issues, service tech is probably $25-30 hour at most unless you happen to get lucky with master tech at $40-50 hour. Trip #1 cost Ram (warranty $350+) as I saw the paperwork I had to sign for the warranty work. Now, since the service tech couldn't properly diagnose and do a thorough diagnostic test, let's set up another appointment with the same service tech, then let's add an engineer or maybe 2 to come up with a resolution. Would love to know what those engineers are getting paid hourly to step in as I asked the service advisor if I needed to sign any paperwork like last time and she advised the case is still open since the ITCM is on backorder. AND we wonder why these trucks are so expensive! 240 miles added to the truck so far, 3/4 tank of diesel (2 trips to dealer with boat) and still isn't fixed.

 

[Gunny7156]

3rd trip to dealer is a winner.....so far. ITCM replaced along with a few loose pins at the ITCM connector and all is good. Not sure why it took 3 trips, 324 miles added and full tank of diesel of get this rectified but it's finally fixed.