I have the factory tow package on my 2500 with the Chysler installed Round 7 RV style plug. I am rewiring my car trailer and would like to use the all time hot terminal (upper right as you look at the plug on the truck) for charging my breakaway battery and utility lights on the trailer. All I can get out of that terminal is 0.3 Volts with ignition on, igniton off, makes no difference. The maxifuse and relay under the hood for the trailer wiring is fine.

What else could be preventing me from getting current? Dodge did hook that up to an all time power source, right?

 

no that should be a keyed source (there resoning being that if you leave your traler hooked up and its drawing power it could kill your batt if the truck is sitting off for a while)

i dont know why youd only be gettng .3 volts, pull the plug out look at the inside, they are notorious for corroding if its fine then you half to have a short somewhere, are you sure the relay/fuse are good im not trying to be an a$$ but how did u check them? to me sounds like 1 of 3 things
1 bad plug
2 bad relay
3 short (fuse would/should have blowen thow)
see if you can visually follow the wire to the front is there a melted/crushed/bad spot?

if you cant get it working i wouldent wast too much time on it just run a new wire (sometimes easer and cheper in the long run) if you want i can tell u how to rewire it with a new relay/silonoid and fuse

 

Hello,

Woohoo...! First post.

Anyone know where to get a decent priced adapter? 7 to 4.

 

the 12+ is not a keyed source from what i recall, the relay does NOT provide power to that terminal, it's an always on....the relay that taps off that line is for the trailer running lights so that you don't use the light switch for that load and burn it out.

 

there will be a relay/fuse for the traler power somewhere dependng on how its wirred there may be a relay for the park lamps and such but its that not common

 

I would like to know where the source is tapped from. The relay checks out because I can hear it clicking when I have the lights on and I pull it out and put it back in. The Maxifuse is good because when it blows my trailer brake control doesn't get power, IE no little red light (ask me how I blew that one, not.. )

I have gone through all the obvious stuff, check the terminals, used a mutlimeter as far as I could to go back, I just can't figure out where the source is tapped from. I understand that you weren't trying to be an a$$, there are some people you need to check the simple things with, but I consider myself mechanically inclined and have rewired several vehicles from ground up as well as worked on old trucks from the time I could hold a wrench.

When you say rewire with a new solenoid/relay (I assume you mean relay as a solenoid is the electrical plunger that engages your starter gear) are you saying that
A.) the source is relayed in my power distribution box under the hood seperate from the trailer lights relay
B.) the source comes from the "Trailer Lights" relay
C.) Add an auxillary relay/fuse setup for the hot source?

I am sure I can figure this out if I can only fine out where ther current comes from.

Thanks for the help guys!

 

source will come from the PDC ithink the the traler lights and aux power share a common souce inside the PDC but ive never looked inside to be sure lol

i would say if you have traced it back to under the hood and cant find the cause of the problem then i would C.) Add an auxillary relay/fuse setup for the hot source

also the brake controler (if you are using the OEM plug in the cab) uses a diffrent fuse than the traler power i belive #5 is brake controler and #8 is traler power (im going from memory thow lol)

also just because a relay is clicking dosent mean the contacts are connecting inside, just that the magnet is pulling, i like to swap the realy with another you know is good to check them (personal prefrance)