Trailer Wiring Question

[ddivinia]

I bought a new trailer and it requires the center pin to be hot and mine is not. My Ram has the factory trailering package. I don't see any blow fuses and nothing in the owners manual about it. I have not broken out the service manual yet. Any quick advice on getting my center pen to be hot?



2005 Ram 3500



Thanks,

D.

 

[jelag]

I can only assume you purchased a new used trailer... .

Since your truck is wired to a national standard for trucks and almost all trailers are wired to a national standard for trailers to match the trucks I'd suggest that you rewire the trailer to match the truck. . thus anyone who might hook up to that trailer could use it...

Any parts store, Autozone, even Wal-Mart has the wiring diagram included in the male or female end... or a search of the towing section of this board would turn up many posts of those who have put that diagram on this board...

Hope this helps. .

 

[PBJ2500CTD]

What is the pin count on the tralier's plug? Depending on the plug - if it a 7 pin plug the center pin is usually the back-up lights. On the 6 pin it is battery voltage.

 

[PBJ2500CTD]

Try this website for wiring info - Trailer Wiring Diagrams

 

[ddivinia]

I can only assume you purchased a new used trailer... .



----



Np - a brand new Featherlite livestock trailer. All the lights worked on their truck at the dealer - mine does not seem to have power on the 7 pin. The dealer said that is not uncommon.



Unfortunately their techs had that Saturday off.





---

Since your truck is wired to a national standard for trucks and almost all trailers are wired to a national standard for trailers to match the trucks I'd suggest that you rewire the trailer to match the truck. . thus anyone who might hook up to that trailer could use it...



Any parts store, Autozone, even Wal-Mart has the wiring diagram included in the male or female end... or a search of the towing section of this board would turn up many posts of those who have put that diagram on this board...



Hope this helps. .

---



Truck is the issue,not the trailer.



I checked all the fuses, etc. There does not seem to be one for pin 7.



Must be a wire hanging in the engine compartment waiting to be hooked to a breaker or something.



D.

 

[ddivinia]

What is the pin count on the tralier's plug? Depending on the plug - if it a 7 pin plug the center pin is usually the back-up lights. On the 6 pin it is battery voltage.

7-way RV plug on the trailer



Truck is not putting out +12 on the 7 pin in the connector.



D.

 

[PBJ2500CTD]

Put it in reverse and I'll bet you'll get 12VDC when your back-up lights come on.
As Jim said, I'd re-wire the trailer's plug to meet the national standard. That way the trailer can be towed by most "properly" wired vehicles. My guess is the trailer manufacturer has done some hybrid wiring - 6 pin to 7 pin "creative" wiring... many have experienced blown fuses when towing other people's trailers that were not wired to a standard.

 

[PBJ2500CTD]

Your truck should have battery voltage(12vdc) on pin 4, the upper right pin from the keyway.

 

[MoparDave]

Hope this helps, center pin is only hot when reverse is engaged.

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[cojhl2]

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Truck is the issue,not the trailer.



D.

The connector must be a flatpin 7way?



What is the trailer expecting from that center pin?

 

[ddivinia]

The connector must be a flatpin 7way?



What is the trailer expecting from that center pin?

RV 7 way



Factory on truck

factory on trailer

no adapter



I'll try it in reverse.



D.

 

[cojhl2]

While what I am asking is what is not working on the trailer? That should give some clue what should be wired there.



I have seen some wire hookups where the center pin(incorrectly in my opinion) used for 12V constant.



Personally i never have a constant even with the standard battery pin hooked up without a switch.



Didja try what PBJ2500CTD suggested? Does the trailer have BU lamps. What more on a trailer can there be?



On some trailer hookups marker lights are seperate from tail lites butI have never seen that with 7pin RV.



Let us know what you find.

 

[PBJ2500CTD]

FeatherLite Owner's Manual

Featherlite's website has the plug pin-out diagrams they use in their trailers - Here is a stock trailer's owner's manual. http://www.fthr.com/userfiles/featherlite-enclosedmanual.pdf Check out page 71 for the different plugs they use. According to their diagram if you have a standard 7 pin RV plug it should be wired to the "standard". If you are expecting something other than back-up lights on the center pin of the RV 7 pin plug, something would surely be amiss. ... Like wired to the semi and not the RV standards.

Bruce

 

[ddivinia]

Guys - the trailer wiring is fine.

I have 5 other trailers that everything works fine with this truck, but they don't have the backup/aux requirements that needs juice on pin 7.

This trailer has interior lighting, etc.

Truck is not putting out juice on pin 7 of the 7 way RV plug - that is the issue.

From reading on other forums - many manufacturers don't make that pin hot. Typically the wiring is there, but it has to be hooked up to a power source with power protection, etc.

D.

 

[ddivinia]

While what I am asking is what is not working on the trailer? That should give some clue what should be wired there.

I have seen some wire hookups where the center pin(incorrectly in my opinion) used for 12V constant.

Personally i never have a constant even with the standard battery pin hooked up without a switch.

Didja try what PBJ2500CTD suggested? Does the trailer have BU lamps. What more on a trailer can there be?

On some trailer hookups marker lights are seperate from tail lites butI have never seen that with 7pin RV.

Let us know what you find.

What is working:
running lights
brake lights
turn (L & R)
Electric brakes

Interior lighting does not work. I have some LED strip lighting in the cattle area and I have a couple dome lights on switches in the front cargo area.

My exterior load lights (rear and side) don't work either. They are all on switches.

No juice on pin 7 from my truck is hosing me.

Also - truck in reverse (running or not) did not energize pin 7.

D.

 

[cojhl2]

Well it does say in the Featherlite manual the 7pin is for aux. I guess that is why I've seen that pin hot.



Well if that is what they want, it should not be rocket science to hook it up. I would do it thru a switch and breaker though.



If someone could get to the manual and check for a wiring dia we could see if there is already a Dodge solution, which I doubt.



And since the standard is either aux/or backup I can see why Dodge did not prewire it.

 

[PBJ2500CTD]

What is working:
running lights
brake lights
turn (L & R)
Electric brakes

Interior lighting does not work. I have some LED strip lighting in the cattle area and I have a couple dome lights on switches in the front cargo area.

My exterior load lights (rear and side) don't work either. They are all on switches.

No juice on pin 7 from my truck is hosing me.

Also - truck in reverse (running or not) did not energize pin 7.

D.

Logic check: Let's see... 5 other trailers work OK with the truck... New trailer doesn't... Hmm, which could it be - 5 trailers and a truck - or the new trailer that may have been incorrectly wired at some time during or after manufacture. New trailer has additional feature of interior/aux exterior loading area lighting. Since most trailers do not have back-up lights many shops will commandeer this "unused" pin and throw in whatever circuit they want - which causes interesting problems when later hooked to a properly wired vehicle. If you open up the trailer's plug I bet you will find the wire that controls your interior lighting connected to the center pin (7) (similar to the semi and/or 6 pin plugs) and not the Pin 4 of the RV plug where the battery voltage will be found to supply power for the interior lighting.
You may want to recheck your fuses, especially the one that protects the back-up lights. If your trailer was mis-wired and your trailer interior lights were on when you passed the gear selector through reverse, you may have blown the fuse.
Then another scenario could be that the truck wiring has been modified... The best thing to do is confirm the trucks wiring is correct per the diagram listed earlier and wire the trailer to match. This way you can hook to any properly wired trailer with no problems. If you run B+ (battery voltage) to pin 7 to accomodate your aux lighting then pull your buddy's trailer with back-up lights - guess what will remain on at all times you're hooked up - yeppers... the back-up lights.

 

[PBJ2500CTD]

Well it does say in the Featherlite manual the 7pin is for aux. I guess that is why I've seen that pin hot.

Well if that is what they want, it should not be rocket science to hook it up. I would do it thru a switch and breaker though.

If someone could get to the manual and check for a wiring dia we could see if there is already a Dodge solution, which I doubt.

And since the standard is either aux/or backup I can see why Dodge did not prewire it.

The center pin on the Dodge's are pre-wired for the back-up lights - usually going through a 10 amp fuse (wimpy, wimpy, wimpy). Pin 4 is the aux (B+) connector that should be protected with a 40 amp fuse in the PDC. This is the connection that can handle all those exrta electrical loads such as interior lighting, electric brake circuit, etc.

Bruce