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KHBama · 06-22-2018, 08:45 AM

Hey Guys,

My battery is not charging while hooked up to my truck. I have 2 7 pin plugs and the lights work while connected to both. I've checked the fuse box and can't find any blown fuses. Any suggestions?

plasma800 · 06-22-2018, 08:49 AM

From what I understand that charge wire in most trucks is too small to carry enough electricity to actually charge a battery while driving. Some people have run a heavier gauge charge wire directly from the fuse panel to the plug, I don't know if that really works but it gives you something to google.

RoadrunnerII · 06-22-2018, 09:39 AM

What year brand model truck?
On our previous truck(2013 f150 screw fx4) the fuse and relay where not installed. They where in a bag in glove box. Friends 2010 Chevy 1500 same thing. Get out the owners manual and look up the fuse panel under the hood. Make sure the fuse and relay are installed. Double check the in cab panel as well but pretty sure that fuse and relay are under hood. Quick check is the 7 pin with ignition on has 12volts on pin 4

Search on Google for the 7 pin wiring layout. Can't add the image for some reason.

RoadrunnerII

twinboat · 06-22-2018, 10:12 AM

Here is an image of the connector.

You need to see if there is power at pin # 4.

Click image for larger version

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tuffr2 · 06-22-2018, 10:44 AM

Agree with look in the glovebox for the square looking fuse. Or owners manual and look at the fuse diagram and try to match that to what you physically see the the trucks fuse box. You might need to go to the auto part store for the fuse.

wildcatter · 06-22-2018, 11:02 AM

If his lights are working he is getting 12 volts to the trailer, I have a 2014 RAM and I can only maintain the battery (maybe of an 8-10 hour trip it may charge it a little bit), they are not designed to charge a battery, now if he is not able to maintain the battery charge than that is an issue, or if he is towing short distances that will also be an issue if he has low batteries, IMO, there is not enough information to come up with a conclusion.

twinboat · 06-22-2018, 11:33 AM

Quote:

Originally Posted by wildcatter

If his lights are working he is getting 12 volts to the trailer, I have a 2014 RAM and I can only maintain the battery (maybe of an 8-10 hour trip it may charge it a little bit), they are not designed to charge a battery, now if he is not able to maintain the battery charge than that is an issue, or if he is towing short distances that will also be an issue if he has low batteries, IMO, there is not enough information to come up with a conclusion.

I would think he's talking about the tail and brake lights. They have nothing to do with the charge line.

If the charge line is connected, he should get some charging.

Maybe something's wrong with yours.

Clomok · 06-22-2018, 01:19 PM

Chevy has to have a fuse and a wire installed to one of he 2 studs on the fuse panel under the hood on the drivers side, it’s not connected from the factory. The wire should be taped to the main wire harness coming outta the fuse box.

jelag · 06-23-2018, 02:21 AM

Modern Light Trucks have the charging circuit controlled by the engine ECM and most have some kind of battery temperature sensor located under one of the batteries.... on a cold day/battery the ECM will increase the charging voltage to overcome the batteries temperature, on a hot day the ECM will cut back the charging voltage..

Remember that years ago we used to add water to the batteries at least once a year or sometimes at every service... that's because the charging system kept the batteries up to full charge.. Today's modern systems means that the battery will go its complete life with little or no water added... and if you check the static voltage of the battery at rest you will find its only 75% charged.. all this lengthens the life of the batteries... also remember that today's modern engines usually start in 4 or 5 rotations, very quickly compared to 20 years ago...

I've found a kit, which when installed takes you low charging voltage and converts it to an adjustable charging voltage in a trailer to bring the trailer batteries to a full charge... however the kit requires a 10 gauge wire and ground down the truck and to the RV.... the kit... is $400 and to date I've not bought it.. I'm still trying to figure out if I can confuse the battery temperature sensor under my drivers side battery...

Hope this helps you understand what's going on..

egwilly · 06-23-2018, 03:53 PM

Like others have mentioned, this circuit is not large enough(amps) to charge anything. It might maintain your battery if you drive long enough(if not dead or under 50%).

At least this has been my experience over the years.

wingnut60 · 07-02-2018, 10:16 PM

Need some info on the truck--also, if the charging wire at the plug has power.
As mentioned, the power is barely enough to maintain well-charged batteries, you'll never have enough to charge 1 or 2 batts from medium to full charge.

SafeDave · 07-03-2018, 08:09 AM

Not sure what truck you have but the new Fords do not charge until you step on the brake pedal. If I do this right the bulletin is attached

Q-263_Trailer_Tow_02212017.pdf

KHBama · 07-04-2018, 10:39 AM

Quote:

Originally Posted by SafeDave

Not sure what truck you have but the new Fords do not charge until you step on the brake pedal. If I do this right the bulletin is attached

Attachment 209419

It’s a Ram 2500 and it ended up being a fuse. It was a 30amp fuse that was shaped different than most fuses. I couldn’t tell by looking at it, looked like the other 30amp fuses that are good. Replaced and boom, back working