Another right trailer light issue

[Moore887]

HI. I own a small pool cleaning business and I tow a new utility trailer with my Ford Maverick Hybrid. I occasionally get errors says that there's a trailer control module issue and a right trailer light fault. The fault will always happen when it rains (which is when I REALLY want the lights to work correctly).
I have been approached by law enforcement when parked outside a house with my hazard lights on because it looks like I am about to pull out with only the left blinker working.
I have been to our local dealership twice and they can't find the fault.
I have it back there again but they called me looking for the trailer now. I already gave them a trailer light tester and they say the TSB requires the trailer. I used my spare truck to bring the trailer to them (an hour away). I told the service advisor that we are now not only down a truck, but a trailer (I don't own a spare trailer) and obviously a tech waiting around today for the trailer. The Ford service advisor told us that if we're in a hurry that we should just take the whole lot away. I decided to leave it there but asked him to get to it as soon as possible. I will hire and kit out another trailer. I can also buy the dealership a cheap trailer for testing purposes because the downtime now is running into four figure sums.

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[OleFordGuy]

That is nuts. Might be wrong but can't imagine the tsb requires the trailer for this recall issue. As long as it test good with the tester and their other testing means, that should be it. If it fails afterwards with the trailer connected then common sense would indicate there's an issue with the trailer components.

 

[Hot Runr Guy]

That is nuts. Might be wrong but can't imagine the tsb requires the trailer for this recall issue. As long as it test good with the tester and their other testing means, that should be it. If it fails afterwards with the trailer connected then common sense would indicate there's an issue with the trailer components.

it appears as though a tester might not be enough,,,,

https://static.nhtsa.gov/odi/tsbs/2023/MC-10236029-0001.pdf

HRG

 

[OleFordGuy]

Hum wow. Guess in today’s world nothing should amaze me. Certainly no mechanic here but in my elderly mind , the wiring is either right or wrong, so if the wiring is correct then what’s left is another recall for different software programming to compensate for different electrical draw ????

 

[Dad's Car]

HI. I own a small pool cleaning business and I tow a new utility trailer with my Ford Maverick Hybrid. I occasionally get errors says that there's a trailer control module issue and a right trailer light fault. The fault will always happen when it rains (which is when I REALLY want the lights to work correctly).
I have been approached by law enforcement when parked outside a house with my hazard lights on because it looks like I am about to pull out with only the left blinker working.
I have been to our local dealership twice and they can't find the fault.
I have it back there again but they called me looking for the trailer now. I already gave them a trailer light tester and they say the TSB requires the trailer. I used my spare truck to bring the trailer to them (an hour away). I told the service advisor that we are now not only down a truck, but a trailer (I don't own a spare trailer) and obviously a tech waiting around today for the trailer. The Ford service advisor told us that if we're in a hurry that we should just take the whole lot away. I decided to leave it there but asked him to get to it as soon as possible. I will hire and kit out another trailer. I can also buy the dealership a cheap trailer for testing purposes because the downtime now is running into four figure sums.

Without knowing what kind of trailer, you have, or how it is wired, here is my story.
I have a light duty tilt trailer. Had intermittent trailer light problems. The ground (negative) system used the chassis of the trailer for return current. Most trailers do this. I still have incandescent bulbs. Ran ground wire from connecter to the mounting of the taillight (left side). Lights are very bright and work every time. I have helped other people over the years with other kinds of trailers. A classic is lights mounted to an aluminum body on a steel frame.

 

[Johnkn]

Irrespective of whether the trailer is new or not, it very well could be a bad ground or light socket on the trailer that is worsened in wet weather.... Especially with small, inexpensive trailers.

I would have cut the problem in half and tried a different trailer with your Maverick, then you know which side of the trailer ball the problem is.

good luck...


.

 

[Moore887]

Irrespective of whether the trailer is new or not, it very well could be a bad ground or light socket on the trailer that is worsened in wet weather.... Especially with small, inexpensive trailers.

I would have cut the problem in half and tried a different trailer with your Maverick, then you know which side of the trailer ball the problem is.

good luck...


.

I may end up having to get another trailer. It looks like they will be keeping the truck and the trailer until they can get time to look at it. So much for Ford PRO!

I don't want to start badgering the service rep, it's like sending food back at a restaurant, you don't know what they're going to do behind closed doors. Kitting out a new trailer with pool equipment may be the best option.

 

[MetalsGeek]

It sounds like your trailer might actually have a corroded connection on either hot or ground to the right lamp. As a hardcore DIY type who loves building special test equipment, I might get a trailer plug and a couple of lights (LED or incandescent, to match what's on your trailer) and create a tester. If the cable is 3' long, you could set it on the top of the tailgate and see how the signals come from the truck while you drive. Any problems that show up on this would be easy to demo to the dealer, and they are guaranteed to LOVE your tester.

 

[Moore887]

It sounds like your trailer might actually have a corroded connection on either hot or ground to the right lamp. As a hardcore DIY type who loves building special test equipment, I might get a trailer plug and a couple of lights (LED or incandescent, to match what's on your trailer) and create a tester. If the cable is 3' long, you could set it on the top of the tailgate and see how the signals come from the truck while you drive. Any problems that show up on this would be easy to demo to the dealer, and they are guaranteed to LOVE your tester.

We may go down that road yet however, the trailer lights perform perfectly with the other two trucks we have. Also the trailer tester we have bought from Advance auto shows the faults on the Maverick.

 

[MetalsGeek]

Assuming that tester is one of the plugs with 3 LEDs on it, I would think that would be enough evidence for the dealer. If your travels educate you on how much current it takes for the truck to detect the presence of a trailer, please share. I seem to recall that the small LEDs on such a tester are detected as a trailer being present. I wonder if any of this could be related to recall 23C41 on the turn signal outage detection.
From what I can tell, the Turn & Stop lamps may be monitored for an open circuit, but the tail lamps are not. The wiring diagrams may not show every internal detail...
The 4-pin trailer plug gets Tail/Parking light power from a relay in the Battery Junction Box that's controlled by the Body Control Module. Each of the Turn/Stop lamps is powered from the Trailer Tow Module that sits on the bulkhead behind the left rear seat. The Left Turn is a yellow wire, Right is green, and Tail is brown. I think these colors are industry standard for 4-pin trailers and run all the way from the trailer plug to the Tow Module. There are 2 connectors between the tow module and the trailer plug. The first of these (starting at the plug) is an 8-pin connector behind the bumper, not far from the tow receptacle. The next one upstream is a MUCH larger 52-pin connector under the left rear of the truck bed. Connectors are always potential problems, I think. I miss the good old days when things were hard wired with a manual switch...

 

[Rad1952]

Did you ever get this sorted out. My 24 EB comes up with a trailer module fault as well. I rarely use my trailer 2-3 times a year so i haven't gottt to far into testing my trailer with another vehicle, or my Mav with another trailer but i’m also not trying to give up the Mav after i just got it.

 

[BlueRaven]

zero issues with either of my trailers, on both my 22 mav eb and 24 mav eb. and i have towed uhual trailers and no issues there too.

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