Battery not charging when in tow

[wyo7011]

I've got a 2011 19bh jay flight. My inverter was completely shot and was replaced under warranty at the dealer, which is 100 miles away. When I got home, I noticed my battery was almost dead and the lights on the status panel only showed 1/4 lit up when plugged into the truck. When plugged into shoreline power, all 4 lights light up and charges the battery. Any suggestions? If I remember correctly, all 4 lights should come for battery power when plugged into the truck as well, correct?

[RoyBraddy]

If you are using a 2009 and UP F series FORD truck the TRAILER TOW DC VOLTAGE is controlled by a FUSE and a BLACK PLUG-IN RELAY in the truck fuse panel.

Look in the FORD TRUCK MANUAL for these two positions in the fuse panel.

My new 2010 F150 Truck had these two items in an unmarked envelope in the truck glove box. Apparently this only allows the TRAILER TOW DC VOLTAGE to be "ON" when the truck ignition key is turned on.

I don't know about the other brand trucks.

You mention INVERTER above - I assume you mean CONVERTER/CHARGER. This should not have anything to do with your truck not sending 12VDC to trailer when the truck ignition key is turned on.

You should read the 12VDC from BLADE 1 (GND) and BLADE 4(12VDC) at the truck 7-way receptacle whne the ignition key is turned on.


On your trailer side the 7-way TRAILER PLUG BLADE 4 should be directly connected to your trailer battery POSITIVE 12VDC terminal. There may an in-line fuse there as well.

sample photos from google images.

The wire colors shown on these two photos sometimes differ from the different manufacturers.

I would look around where the Converter/Charger unit ground connections were made - the warrenty replacement may have left some wires off near the battery terminals...

I assume all of this worked before TRAILER TOW 12VDC wise before the converter/charger was repaired.

BTW Most of us usually has an entry on what we are using Truck and Trailer wise either listed with the post or at least in our profile. Lets everyone know what equipment we have.

Roy Ken

[THABULL]

On my 06 Chevy the battery prong on the truck receptacle did not come from the factory hot. If you have a test light check to see if the battery prong in the receptacle is hot. My truck came from the factory with a dummy fuse for that curcuit in the fuse box under the hood so it was just as simple as putting a fuse in to complete curcuit.

[wyo7011]

My tow vehicle is an '08 dodge 3500 cummins. All the lights and everything appear to work just fine when plugged into the truck. I've already checked all the fuses, including the 30 amp fuse near the battery. All are intact. I'll mess with the plugs today and see what I can find. Thanks for your help.

[wyo7011]

I just went out with the multimeter. The battery reads 12.6 volts with nothing connected. When connected to shoreline power, it increases to 13.8 volts. When connected to the truck, the battery voltage doesn't change and stays at about 12.6. I also checked the plug on the truck and can only get anywhere between 2.3-3.5 volts and it fluctuates a lot. I that a normal output?

[RoyBraddy]

Did you turn your Dodge truck ignition key "on"

Put multimeter leads on blade 1 and blade 4 on the truck side. My receptacle has a small wiring diagram imprint on it on it. Looking for GND and 12VDC BAT

Did all of this work OK before you took the trailer back for warrenty work?

Roy ken

[RoyBraddy]

Try this as well... With the trailer PLUG held in your hands connect the multimeter to the blade 1 and blade 4 and see if you read the 12.6VDC there.

If you can read your trailer battery there then the trbl is on the truck side. Fuse? Ignition OFF? bad ground between truck and trailer etc... Seems like i remember the DODGE trailer blades being always hot - may be wrong there...

Roy Ken

[Jagiven]

Once you confirm you have aux power to the female end of the 7 pin connector I would wonder if you have a loose wire nut. Where the 7 pin wire harness enters the TT there is a wire nut with two wires (3 wires total) connected to the red battery wire (Aux power from the TV). If this wire nut is loose or a wire was never fully engaged when it was tightened down it might have vibrated loose and you are not getting power from the TV to the battery.

Otherwise I would confirm that the battery has not gone bad. Two options; if you have a charger at home plug the TT battery in and let it take a full charge. If it does take a charge and hold the charge the battery most likely is good. Otherwise pull the battery and bring it into an auto parts/repair shop and have it tested.

When plugged into the shore power the indicator lights ALWAYS show four lights and charged. You need to unplug the shore power and then test the battery after a few hours to see if the battery took a charge.

[wyo7011]

Yes, I tried all of this with the key off/on/ engine running, with no change. If I disconnect the shoreline power, the battery reads like 12.6, and 12.6 when it's fully disconnected. I tried the multimeter on the ground prong and 12v prong it's still reading around 3 volts. When I pt a draw on the battery, my monitor LEDs with slowly drop 4-3-2-1 as the charge drops. I'll pull that cover off tomorrow where the cord connects to the TT and see if anything is wrong there, and look for some fuses in the truck. Thanks for the help so far, at least I feel like I can make some progress by knowing what to look for.

[wyo7011]

I just went out and plugged the multimeter into the cord on the TT. Wen I plug into the respective power and ground terminals, I get 13.51v when plugged into shoreline, and reads 12.4v with no external power attached. I guess it's the truck that's not working.

[wyo7011]

Doh. I didn't think to check the fuses. The 30 amp trailer power fuse blown blown. Now I get a crisp 14.4 volts. And you guys were right, dodge trailer plugs are always hot.

[Chakara]

Love my Dodge - but remember this if you stay plugged in with a fridge that can run on DC or at the campground for an extended time. Easy way to kill the trailer and TV batteries at the same time! (don't ask how I know!)

-Chak

[wyo7011]

Chak, thanks for the tip. I believe my fridge runs only on propane or when plugged into shoreline power. But I've thought about leaving it plugged into the truck when the engine isn't running, it would probably kill the truck batteries too.

[RoyBraddy]

Glad its back... AT least next time you know what and where to check...

I always squirt alittle WD40 into the truck connector before plugging in the trailer connector. Then move it around pretty good to keep the contacts clean. Some guys like to put the Dielectric type greese on the connections.

I have had my trailer plug not get locked in place with its lid sometimes. My older FORD really locked in place using the lid where this 2010 model dosnt do as well. If it gets worse I may use some short stretch rope to hold it in place...

The 30AMP on mine had to be changed to a much higher current rating when I changed my converter/charger to a PD9260C 60AMP unit. I Think I have a 80AMP inline fuse in it now. I am also running three 85AH batteries. Most single batteries have the 30A fuse, dual batteries have 45AMP-55AMP fuse. etc... When I am charging with my PD9260C 60A Inverter I have read 14.4VDC@52-53AMPS being put back into my three 85AH battery bank from the Inverter/Charger unit.

I installed a battery monitor panel to watch my battery functions all the time. The Bogart TRIMETRIC TM2025RV is a good monitor system to use as well as it has built-in alarms.



Roy Ken