I would like to find out what I need to do to get constant power to terminal # 4 on the factory 7 prong connector at the rear bumper. I would like to be able to supply constant power to an aux. battery in my enclosed trailer. All fuses etc. identified in the owners manual as involved with tow package are good and running lights, turn signals, electric brake work okay? Any help would be appreciated.

hugger 94

 

There is already a constant power (switched) when the vehicle is turned on. I don't know what color it is on your truck, but it is the one to the direct right first position at the top on a seven prong plug. When your key is turned on, it should be live.

 

Some vehicles need the relay for it installed first. I believe its in the power distribution box under the hood.

 

Sorry, I forgot that. Yes it is true. If your towing package is not factory, you need two relays added to use the seven prong plug. Or I should say one relay and a half relay. (means one square one and one half that size)

 

My tow package is factory. Which relay(s) are needed in the power distribution panel? I have power to the trailer interior 12 volt lights with the switch on and the head lights on. I am wanting to be able to charge an aux. battery in the trailer (wench) as well as be able to use my 12 volt interior lights without having to have my truck engine and lights on.

Hope I am making sense!

hugger94

 

Okay, this may take some time. If you are talking about a camper trailer, and I will continue as if you are, the following will apply.

Your interior lighting in the trailer should come from a battery which is installed in the trailer itself, and is for use only by the 12 volt system inside the trailer and for one item outside, which is a breakaway for your brakes on the trailer if your trailer is equipped with brakes. Your interior lighting in the trailer should not come on with the truck power unless you HAVE a battery in the trailer, which is drawing some power from the truck when it is running. This would normally be a black wire, and it does charge the trailer battery to a small amount when your vehicle is running. You DO NOT want the interior lights to be on from your truck power when the truck is not running, because then you will draw down the truck battery and may not be able to start the truck when you want or need to. When you turn on your truck lights, the OUTSIDE lights on the trailer should come on, both tail lights and marker lights. There is a great possibility that your trailer plug is not wired to match your truck plug if the trailer is more than ten years old. Almost everything from 1989 to the present was wired correctly, or I should say "To the same standard" and from 1989 to about 1994, there were some that were not wired to that same standard. Another thing to note is that someone may have rewired the trailer to match a wiring job that they did personally on the vehicle towing the trailer, so they Might NOT be wired to standard. If this is the case, then you need to know the standard for the trailer so that you can rematch it to the truck, which is Factory and so is to the standards used today. It would help me to help you if I knew all about what you are towing, and what you are towing it with. I do see from your first post that all external lights and the brakes are working fine. Now, if your question was only how to run full time power to your utility trailer, I would advise against it, due to the reasons I stated above. Let me know if I helped or if you need to know more. Oh, and don't worry about the relays, because if everything including your brakes are working on the trailer, the relays must be in place.

Thom

 

Sorry I should have indicated that my trailer is a 2001 Pace 20' enclosed so it is wired normally. I did check the upper right contact marked (+) on the cover on the pickup. It was live with the ignition on. I will now check into the wiring box underneath the trailer to determine the wire for the 12 lights and run it off the aux. battery. Thanks for your help, it is greatly appreciated.


hugger94