Here is what I've found after spending a couple hours this morning working the issue. When the truck is not running, there is 12.8v in the truck battery and 12.8v at the plug at the bumper. When running, there is 14.2v at the battery and 12.8v at the plug. The trailer battery has 13.08v while just sitting there. I've had the trailer hooked up to shore power for the last week so would expect the battery to be fully charged. When I plug the trailer into the truck while running, there is no difference in the amount if voltage to the trailer battery. It maintains the 13.08v. If I disconnect the positive lead wire on the trailer battery, all the lights (turn, brake, running, etc.) on the trailer work if the truck is connected and running. Now this is the part that I am really confused about; if the truck is hooked to the trailer with the truck running and the positive wire to the trailer battery disconnected, there is no power coming to the junction box on the frame where all the wiring connects from the trailer pig tail to all the trailer wiring. I opened the box to check all the connections which are held together with wire nuts and the black wire (hot lead) from the pig tail has no power coming from the pickup. I would think that since the trailer lights are all working, it would get it's power from the main power lead coming from the pickup. Anyway, I don't think I'm getting a charge to the battery from the pickup since it is fully charged and doesn't need one. I need to let the battery run down some and do the same check on voltage to see how much the pickup is providing to the trailer battery when it's low. Bottom line so far, not sure if I have an issue or not. That's part of the reason for the shake down cruise to ferret out what works and what doesn't. Thanks for listening to all the rambling.
There is a resetable fuse located near the junction box your tow cable goes into. The terminals can be corroded and not making good contact.
The fuse maybe under a red rubber cap and the reset button is on the side.
Look for something like this:
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
When running, there is 14.2v at the battery and 12.8v at the plug.
Since there should be only a wire and some type of fuse (link or resettable) between the battery and the 7 Pin Trailer Connector, they should read the same voltage.
What you posted in the quote indicates an open circuit in the TRUCK, between the 12V source and the Trailer Connector.
"Some" vehicles also use a relay enabled by the Ignition Circuit to provide power to the Trailer Connector only when the Vehicle is running, and prevent the Trailer from draining the Vehicle Battery. These relays are "normally" located in the Fuse Box also.
Have you check in the Truck Fuse box for a fuse labeled Trailer or Trailer Connector?
You should have a battery isolator installed if you do not already have one. This will prevent the trailer from draining the TV battery when plugged in the the 7 way plug if the truck is not running. To check to see if you are getting power from disconnect from shore power, disconnect your battery. Have the TV hooked up to the trailer and try turning on your 12 volt lights inside the trailer. If the lights work then you have power going to the trailer.
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Terry and Janet
2008 3001W Windjammer
2007 Ford F150
There isn't a fuse for a trailer in the fuse box. I'll check for a fuse next to the electrical box in the trailer. Also will check to make sure the relay on the outside of the box is functioning properly. Thanks again to everyone for your help and suggestions.
Here is what I've found after spending a couple hours this morning working the issue. When the truck is not running, there is 12.8v in the truck battery and 12.8v at the plug at the bumper. When running, there is 14.2v at the battery and 12.8v at the plug. The trailer battery has 13.08v while just sitting there. I've had the trailer hooked up to shore power for the last week so would expect the battery to be fully charged. When I plug the trailer into the truck while running, there is no difference in the amount if voltage to the trailer battery. It maintains the 13.08v. If I disconnect the positive lead wire on the trailer battery, all the lights (turn, brake, running, etc.) on the trailer work if the truck is connected and running. Now this is the part that I am really confused about; if the truck is hooked to the trailer with the truck running and the positive wire to the trailer battery disconnected, there is no power coming to the junction box on the frame where all the wiring connects from the trailer pig tail to all the trailer wiring. I opened the box to check all the connections which are held together with wire nuts and the black wire (hot lead) from the pig tail has no power coming from the pickup. I would think that since the trailer lights are all working, it would get it's power from the main power lead coming from the pickup. Anyway, I don't think I'm getting a charge to the battery from the pickup since it is fully charged and doesn't need one. I need to let the battery run down some and do the same check on voltage to see how much the pickup is providing to the trailer battery when it's low. Bottom line so far, not sure if I have an issue or not. That's part of the reason for the shake down cruise to ferret out what works and what doesn't. Thanks for listening to all the rambling.
I don't intend to write anything negatively, so please don't read anything in to what I am asking you to do. I have to be sure of what I am asking and it might seem silly or redundant. Also, if you want to, you can PM me and give me your phone number, we can get to the bottom of this faster via the phone. My gut feeling is you are testing with trailer and truck connected and / or shore power connected, which is causing confusion (it would me) or possibly you have a grounding issue. I had a Trailmanor and you had to push hard to get it plugged in. But to recap from above, it seems the truck battery and charging system is good. However the +13.08 VDC at the house battery sounds a little too high for static battery voltage, but it could be, or maybe it is shore power you are "seeing". The 4way to 7way adapter plugs has 4 other wires, of which 3 are important, the white is to be grounded to the truck frame, the blue is brake, the yellow isn't used but the black is what we are trying to get "working". I wonder if you have a isolator or a battery disconnect switch in place (Y or N) Are you testing with shore power disconnected (Y or N) Keep it that way while testing and for the time being, keep truck and trailer disconnected as well. Have you verified the house battery is grounded to the trailer frame (Y or N). Is it still 13.08VDC (Y or N) across the battery, AND from the + to the trailer frame. Lets call the connectivity from the 40A fuse in the truck all the way to the house battery B+. Its purpose is to get TV fused (40A) battery power to the trailer, to run 12VDC things in the trailer while driving (as a side note - without a house battery, a trailer can drain the TV battery quickly) so this B+, of course, also charges the house battery. This B+ has nothing to do with the running / brake / stop/ tail / lights nor the electric brakes. You said all the lights work. You just need to test at the trailer plug end (still disconnected) that plugs into 7way on the truck to know the house battery B+ is getting to the plug end (pin 4) (Y or N). Depending you the results of the previous, now test pin 4 at the truck connector to be sure B+ is getting back there from the 40A fuse (Y or N). If B+ is on the connector and at the plug on the proper pin (4) you should have continuity. Pin 1 at the truck should be ground (-), again depending on the results above, make sure you have a good ground there. If you have the trucks +12.8 VDC (or higher when running) to the 7way on the truck, through the trailer cable to the battery, it has to raise the voltage at the house battery, unless there is a disconnect isolator or fuse "open" on the trailer. Again, PM me if you need more help. I would love to help anyway I can.
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Hyper Lite was sold
2017 F-250 4x4 6.2L Gas
I can't fix everything, but I can make it so nobody else can
Let me try to answer your questions; all tests were done with shore power disconnected, there is no isolator or battery switch, the house battery has a good ground to the frame of the tt, the 13.08 is across the + and - of the tt battery ( I just checked and it's 12.65 this morning after sitting unplugged all night). I'm a little confused about your next question. The truck had a 4-way which was used when I installed the 7-way. I had to add two 10g wires (from the install kit) one to the 40amp breaker (also part of the kit) and truck battery and one to the brake controller in the cab. The only connector in the 7-way not used is the reverse light wire. All the exterior trailer lights work with the tt battery disconnected and the truck running. There is no power coming through the black wire in the trailer pig tail energizing the positive wire which connects to the tt battery. This is the part that I really don't understand. There is power on the truck side of the 7-way but not on the trailer side. The only time the trailer side is energized is when the tt battery is connected. I can take a couple pictures and send them to you if you want to see how it's set up. My email is schultz4953@gmail if you want to send a reply direct or I can call you. I'll do the checks from the second half of your reply and see what results I get. Everything seems to be working through the 7-way except the charging part. 0 camping days in 2013....it's March already???
Greetings and here's an update. Spent this morning doing some additional testing on the charging issues we have been discussing and "what do you know" a solution. As you may recall, my original testing was done after the tt had been hooked up to shore power for over a week. Since the battery was fully charged, there was no charging going on when the pickup was plugged in and tested. The tt has been unplugged from the 110 for a few days and the battery has dropped to about 12.45v. Today I plugged the pickup to the trailer and checked the voltage to the tt battery and it showed a charge of 13.02v while the pickup was running. If I had just waited a few days (unplugged from shore power) the original testing would have showed what I had expected. It's true that I don't have an isolator between the pickup and tt which is something I will think about doing in the near future. I just need to remember to unhook the trailer from the pickup if dry camping for any length of time. I always carry jumper cables just in case however. Thank you for all your input and especially to WolfWhistle and the phone call.
Congratulations on you finding. I bet you feel alot better now. I think you need to go camping to get things off you mind. I think i seen smoke signals in Arizona the last few days. Lol good job
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Ram 1500
Big Horn
Hemi 5.7 2011
Salem 30KQBSS 2012
No smoke this morning....getting a little rain around the valley. Our plan was to hit the road and spend a couple nights at Quartzite but a storm front moved in last night and we'll be getting rain for the next 24-36 hours. We'll hold off a few days before doing the shake-down. 82 yesterday but only 62 today....it must still be winter.
Good posts from all. I have a question regarding this situation. I have a 2009 Chevy Silverado LTZ with 7 pin connector. And I just bought a 2001 Flagstaff from ForestRiver. With the truck hooked up to the trailer and the ignition running, how long does it take to charge the 12v trailer battery?
Good posts from all. I have a question regarding this situation. I have a 2009 Chevy Silverado LTZ with 7 pin connector. And I just bought a 2001 Flagstaff from ForestRiver. With the truck hooked up to the trailer and the ignition running, how long does it take to charge the 12v trailer battery?
That depends on the charge status of the trailer battery, the loads on the truck from other devices and some variables like temperature etc. In general I always followed the rule that an alternator need about 30 minutes to charge a battery that was low.
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2013 Coachmen Freedom Express 320BHDS pulled by a 2005 F250 King Ranch CC
A rainy day camping is better than a sunny day at work.
Good posts from all. I have a question regarding this situation. I have a 2009 Chevy Silverado LTZ with 7 pin connector. And I just bought a 2001 Flagstaff from ForestRiver. With the truck hooked up to the trailer and the ignition running, how long does it take to charge the 12v trailer battery?
for most applications, you'll only get a trickle charge and for a low battery, it will take hours of driving to recharge the battery.
only trucks with second alternators or a optional larger alternators, can supply significant amounts of power to recharge in a shorter time.
expecting your tow vehicle to recharge the battery, is the most inefficient way to do it, unless you're driving for a number of hours.
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Dan-Retired California Firefighter/EMT
Shawn-Musician/Entrepreneur/Wine Expert
and Zoe the Wonder Dog(R.I.P.)
2016 PrimeTime TracerAIR 255, pushing a 2014 Ford F150 SCREW XTR 4x4 3.5 Ecoboost w/Max Tow Package
4pt Equal-i-zer WDH and 1828lbs of payload capacity
Linear Mode
