How to wire up a truck camper

[BigJim]

While I'm waiting for my new truck to arrive I'm trying to get a many upgrades on hand so I can get on the road as fast as possible.

New 2021 Ram 3500 4x4 Tradesman regular cab, 8 foot bed.

I'm going to put a large truck camper on it and travel. I'm trying to find out where is the best place to tap in to the trucks systems for a 7 pin trailer connector.

Note, I'm now towing anything, the connector needs to come up right behind the drivers seat between the cab and the truck bed. This is not a 5th wheel trailer. I'm hoping since trucks are used for camping there might be some place under the truck where I could just plug in. I don't mind paying factory prices if they have what I need. Etrailer.com wasn't any help.

Thanks for anything you can suggest!

 

[H3LZSN1P3R]

Buy the t harness ment to go to the back of the truck box then just cut and extend the wires to bring the 7 pin to the front of the bed

 

[Brutal_HO]

Agree.

Buy the plug and play for the truck side and add a long umbilical if needed.

https://www.amazon.com/CURT-56070-V...t=&hvlocphy=9028763&hvtargid=pla-434869262529

 

[BigJim]

H3LZSN1P3R the truck already has the 7 pin plug installed. I do need to keep both so I can't cut it. I was hoping there might be a junction somewhere underneath that I could just plug into. I have in the past spliced into the truck wiring but was hoping for something a little easier and faster. ​

Brutal_HO I've looked at those but have concerns about so much voltage loss from such long wire runs by doing something like that. I worry that it won't be able to keep the camper batteries charged.​

Thanks for the ideas, I would think that by now new trucks would be a little more "plug and play" .

 

[Brutal_HO]

This works for lights and low current draw 12V and just T's into the back side of the existing bumper plug.

I thought most truck campers were setup to pick those up from a bed located 7-pin.

If you're going to charge batteries, you need to run welding wire or other heavy gauge directly from the HAPP bus on the battery or use a DC-DC charger.

As to length, the 12V supply charges my fifth wheel battery from the front of the truck, through 20 feet of wire and through the umbilical and trailer wiring to the converter that's probably another 25 ft just fine.

Sent from my work avoidance device

 

[H3LZSN1P3R]

Im not saying to cut the oem wires just the t harness as it will only reach the back of the bed not the front.... the gauge of wire thats on the plug already is more than fine for 30A charging thats all i have ever used for keeping my trailer batteries charged aslong as you keep the same gauge as oem you wont have any issue with voltage drop i believe it is 12 or 10 gauge which is addiqute for 30A which is what oem 7 pin positive is fused at.....

 

[H3LZSN1P3R]

I am not sure what the gauge of the OEM wires are but I am confident they are nowhere close enough to being the correct size. Here is a basic video to help explain:

Yes they are gauged for 30 amp you wont use more than that to charge batteries lol hell i can run my dump trailer off the 30A when the battery is dead

 

[H3LZSN1P3R]

This is your OEM trailer harness? Most trailer wiring harnesses are 16 gauge and are not even rated to carry 30 amps at any length.

What is your source of information which states your trailer harness is rated for 30 amps?

The positive and ground are bigger than the rest yes thats oem and it is fused at the fuse box for 30 amp they have been doing that for years even my 01 and 96 were like that..... they are 10 gauge wire which is what you need for 30 amp how do you think they have been charging camper batteries during transport for decades you are way over thinking it.....

 

[Brutal_HO]

Keep in mind that all the fused connections are derated for constant current. 24A on that 30A fuse...

That said, if I were using a DC-DC charger to charge a battery bank, I'd run at least 4AWG wire from the HAPP to the charger unless using chassis ground then you could possibly get away with 6-8AWG.

 

[H3LZSN1P3R]

Not to flog a dead horse but I deal in facts and I don't compromise. The wires in a 7-pin connector are a combination of 12 and 16 gauge - those are SAE standards. The auxiliary power wire (and the ground) we are discussing is 12 gauge and it is not possible to push 30 amps at 14 Vdc more than ten feet or so without voltage loss beginning to go above 3%. And that ten feet is the length of the complete circuit so add your positive and negative runs together. If we want the maximum life and usefulness out of our batteries then we must follow the manufactures recommendations for voltage and time requirements for bulk, absorption and float stages.

When I design and construct mechanical or electrical systems I follow established guidelines and generally accepted engineering practices. I don't overthink anything, I do it the proper way and I deliver valid solutions.

I can put a dvom on my truck batteries and on the trailer batterys any there is no drop....

 

[Jak6four]

While I'm waiting for my new truck to arrive I'm trying to get a many upgrades on hand so I can get on the road as fast as possible.

New 2021 Ram 3500 4x4 Tradesman regular cab, 8 foot bed.

I'm going to put a large truck camper on it and travel. I'm trying to find out where is the best place to tap in to the trucks systems for a 7 pin trailer connector.

Note, I'm now towing anything, the connector needs to come up right behind the drivers seat between the cab and the truck bed. This is not a 5th wheel trailer. I'm hoping since trucks are used for camping there might be some place under the truck where I could just plug in. I don't mind paying factory prices if they have what I need. Etrailer.com wasn't any help.

Thanks for anything you can suggest!

I’m in the process of doing the same thing on my new 2021 3500 to mount my Lance camper. I’m using a plug in “t harness” from etrailer which plugs in to the factory wiring right behind the bumper. It retains the factory 7 pin on the bumper and doesn’t require cutting into the truck wiring. The “t- harness” has a 10 foot lead which will allow me to reach the truck side Lance connector which I will be installing in the front of the bed on the drivers side. The Lance connector uses 8 ga wire for the 12v positive and ground wires so I will be running 8ga wires for both directly to the battery with a fuse on the positive side. The camper has a Blue Sea VSR relay in it which disconnects the truck battery when its not running.
This is the exact same set up I used for several years in my previous Ram and I had no problems recharging my camper battery in just a few hours when traveling between camping spots.

 

[BigJim]

I’m in the process of doing the same thing on my new 2021 3500 to mount my Lance camper. I’m using a plug in “t harness” from etrailer which plugs in to the factory wiring right behind the bumper. It retains the factory 7 pin on the bumper and doesn’t require cutting into the truck wiring. The “t- harness” has a 10 foot lead which will allow me to reach the truck side Lance connector which I will be installing in the front of the bed on the drivers side. The Lance connector uses 8 ga wire for the 12v positive and ground wires so I will be running 8ga wires for both directly to the battery with a fuse on the positive side. The camper has a Blue Sea VSR relay in it which disconnects the truck battery when its not running.
This is the exact same set up I used for several years in my previous Ram and I had no problems recharging my camper battery in just a few hours when traveling between camping spots.

Does your camper have a male connector that plugs into a female plug in the bed? My most recent camper had the female plug at the bottom front of the camper which required me to use a cord with a male end to plug into it.

 

[Jak6four]

Does your camper have a male connector that plugs into a female plug in the bed? My most recent camper had the female plug at the bottom front of the camper which required me to use a cord with a male end to plug into it.

Yes, female connector mounted in the side of the bed with a 3’ lead coming off the camper with a male connector on the end.

 

[H3LZSN1P3R]

Must not be a Fluke with NIST traceable A2LA 17025 calibration from a local metrology laboratory.

Its a fluke but no need to be that fancy i can get 7-10 years out of my batteries good enough for me.....