2009 Trailer/Camper wiring

[LVrooman]

Just upgraded from a 96 3500 to a 09 3500 and I am in the process of getting my new truck ready for the vacation/fishing seasons. I have been reading the problems on the forum in regards connecting directly to the wiring harness and taking out the $400 plus control module. Has anyone done an 09 and are the same concerns there about fusing the right/left/brake lights? Somewhere I read that the LED lights don't put enough of a load for them to work right. I have LED's on my boat trailer but not the camper so I am guessing as long as I have the camper they will work OK since there will be enough of a load but what about when I use the boat only? Thanks.



Lanny

 

[HBarlow]

Just upgraded from a 96 3500 to a 09 3500 and I am in the process of getting my new truck ready for the vacation/fishing seasons. I have been reading the problems on the forum in regards connecting directly to the wiring harness and taking out the $400 plus control module. Has anyone done an 09 and are the same concerns there about fusing the right/left/brake lights? Somewhere I read that the LED lights don't put enough of a load for them to work right. I have LED's on my boat trailer but not the camper so I am guessing as long as I have the camper they will work OK since there will be enough of a load but what about when I use the boat only? Thanks.

Lanny

If your new truck has a factory towing harness you don't need to worry about trailer lights working properly as long as the trailers are wired properly. Just don't plug an improperly wired trailer or a shorted harness into your seven pin female towing connector.

The problem with LEDs not drawing sufficient current to operate the truck's flasher timer only occurs if you try to replace the factory incandescent tail lamps with LEDs. If you leave the factory tail lamps as installed it makes no diffence if your trailer has LED lamps.

I replaced the incandescent tail lamps on my C&C aftermarket bed with LEDs and had to add resistors in parallel to each stop/tail/hazard flasher lamp in order for the flasher to work properly. But I replaced the factory incandescent lamps on my fifth wheel trailer with LEDs and the truck didn't notice or care.

 

[LVrooman]

Thanks for the info Harvey.



That's what I was guessing on the LED's, just wanted to make sure the trailer lights weren't a separate function on the control module and that it needed a load to work properly.



I do have a factory installed towing harness, but I also need a 7 pin receptacle in the bed of the truck for my slide in camper. That is where my concern is with taping into the wiring harness for that plus the additional load the lights on the camper may put on the system along with the boat. That was the reason for putting LED's on the boat to reduce current draw overall.



I read where they were changing the fuse from factory to 10 amp to protect the controller but I am guessing I would be pulling more than that... . with truck, camper and trailer lights. My plans are to purchase a "T" that would allow me to break the wiring harness near the bumper, plug the "T" in then the rear 7 pin receptacle and run the 7 pin receptacle extension to the bed of the truck. Because of the voltage drop in this length of wire I will not be using the 12v supplied by the "T" wiring harness, instead I plan on running a 6 or 8 gauge wire directly from the battery through a 60 amp circuit breaker and 60 amp relay activated by the ignition switch in the run position.

 

[HBarlow]

Draw-Tite Fifth Wheel and Gooseneck Wiring Harness with 7-Pole - Dodge with Factory Tow Package 20111 : Trailer hitch bike rack and trailer hitches - etrailer.com

Here's the T adapter and harness you need. It's a simple plug and play w/o cutting a wire.

It's a good idea to run a separate heavy gauge wire from positive battery post through a circuit breaker to the charge lines to both the bed 7 pin and rear 7 pin as you suggested but it might be helpful to route it through a switched relay controlled by the key. That way you can't accidentally discharge the starting batteries if you run a propane furnace all night in cold weather. I don't think you'll need 60 amp capacity for recharging RV batteries. 30 or 40 would probably be more than enough.

 

[DPalmquist]

Years ago I was towing and needed to put plug on tow vehicle when I spliced into wires I put diodes in, I picked up from some trailer install place they recomended the use of them. But can't remember the amperage size to use, as I am thinking about putting some on my rig. maybe 10 amp and 25 amp on the aux plug? anyone know which size amperage diodes to use. Not trying to take over your orig. ?. thanks

 

[HBarlow]

I'm going to guess you would need diodes rated to carry as much as 30 amps if you have replaced the factory charge line with a heavier gauge wire. If the trailer's batteries were down and you were charging them from the truck you could draw a lot of current. If you continue using the factory charge wire or one the same size it probably isn't capable of carrying more than 10 amps.

I'm guessing so don't plan your installation around my opinion. I guess the starting point would be to check and see what size fuse Dodge installed in the factory charge line. That should tell you how much the factory wiring harness was designed to carry.

On edit: I can't think of a reason to install diodes in the charge line. What would be the purpose? You would always be drawing current from truck batteries/electrical system to the trailer batteries so current would always flow that direction. The only reason current would flow back from trailer to truck would be if the truck batteries were down and the trailer batteries were charged. I don't see the need.

 

[DPalmquist]

Thanks HBarlow, I'll check the fuses and go accordingly. As far as the need for diodes, I was told that just plugging in the connector might cause a jump backwords in current and if you have some bad (corosion) it might acure also. I'm just being to careful of TIPM I guess. later