Forum Discussion

cutty72's avatar
cutty72
Explorer
Nov 08, 2014

Electrical question

Question regarding the electrical system on my TH.
First, it's a 2004 Jayco Talon 36Z 5er.

With the recent birth of my first son, I neglected it and the batteries went dead.
Now trying to move it to my winter storage area, I plugged it in for about a half hour, then hooked it up to tow home.
When plugged in, all the trailer lights were bright. When just connected to the tow vehicle (01 F250) they were dimmer. Also, the brakes did not work without the batteries charged.

So two questions with this.
1) I thought the batteries were separate from trailer wiring (tail/brake lights, running lights, and brakes) and they got power from the TV.

2) Do the batteries need to be charged to operate everything while driving, or did someone rewire stuff and now things are crossed?

Thanks
Toy Haulers
  • offtohavasu's avatar
    offtohavasu
    Explorer
    Nov 10, 2014
    I disagree with those who are saying that the trailer battery does not have an affect on the running lights. Yes you are correct in that the lights do not run directly from the trailer battery. However, as someone has mentioned, if those batteries are toast and causing a large load to the tow vehicle, then yes, the lights will dim when trailer gets plugged in. Supply and demand.
  • BTPO1's avatar
    BTPO1
    Explorer
    Nov 09, 2014
    I agree with what others have said above about you not needing a battery in the trailer for running lights or brakes. That power should be supplied from the TV. You do need a 12 volt power source for the emergency brakeaway system though. I think that someone has changed some of the wiring around some. You might want to spend some time tracing the wiring and see where the problem is. JMO
  • cutty72's avatar
    cutty72
    Explorer
    Nov 09, 2014
    I was planning on replacing the batteries next year anyway, the never held much of a charge.
    I got enough charge in them to make it to storage, but it wasn't "right".
    I know the batteries are required to complete the circuit, because if they aren't installed, I get no lights/brakes on the trailer. I'm just wondering if this is how it's supposed to be, or if something is wrong with it.

    Everything on the tow vehicle is good, no issues with other trailers.
  • time2roll's avatar
    time2roll
    Nomad
    Nov 08, 2014
    Hopefully you left it plugged in overnight and today just drag it to storage.
    Best to pull the bad battery out in winter storage.
    Plan on a new battery when you pull it out of storage in the future.
  • ScottG's avatar
    ScottG
    Nomad
    Nov 08, 2014
    1. The brightness of the tail and running lights has almost nothing to do with your RV battery. It does not power them.

    2. When driving down the road, you don't need the trailer battery and everything will work fine without it - so no, it does not have to be charged. The one exception is the emergency trailer brake function that applies the brakes if the trailer separates from the TV.
  • arhayes's avatar
    arhayes
    Explorer
    Nov 08, 2014
    Power passes from the Tow Vehicle through the battery. However, if the battery is very weak or has shorted cells, it cannot efficiently run your 12v systems. You probably need to have the battery load tested and if it good give it a good charge before using. I suspect you'll find it needs to be replaced.
  • newman_fulltime's avatar
    newman_fulltime
    Explorer II
    Nov 08, 2014
    everything goes through the batts your lights dimmed because your altinator can only do so much.

About Fifth Wheel Group

19,008 PostsLatest Activity: Mar 07, 2025