Not charging battery, but 7 pin connector wired properly.

BigMitch

I've verified my factory installed 7-pin is wired correctly on my truck.  2015 T@B M@X S (so relatively new battery as well).  110 to the shore power charges battery fine.  30A in-line fuse on battery positive is fine.  Here's the interesting part which is probably a smoking gun to someone with more experience in this area than I:

Negative battery lead disconnected: 14.5V showing in cabin with TV running (obviously charging)
Negative battery lead reconnected: 12.2V (barely or not charging, battery is at 11.6 or something right now).

Ideas on what to check next?

USWildflowers

I'm guessing bad cell in the battery. I'd take it to an auto parts store or repair shop to test...

BigMitch

I'll test the battery tomorrow to take that out of the equation, but I think since shore power seems to charge it up fine, it's probably ok...

Cyclonic

There should be a fuse between the tow vehicle battery and the connector, usually under the hood at the battery.  If there is not one there, and it is a factory tow package, check with the manufacturer to find out where that fuse is.

USWildflowers

BigMitch said:

..since shore power seems to charge it up fine, it's probably ok...

Yeah, I missed that.

Nomad

As Cyclonic mentions, check that fuse at the TV battery. Mine was blown and weird things were happening.

BigMitch

It must be something in the wiring going from the battery to ground, or battery to the converter I think.  If it had anything to do with the 7-pin wiring or truck connector, it wouldn't charge at 14.5V with the battery ground off. 

Also, this happens with multiple tow vehicles, not just my truck.

The plot thickens...

Cyclonic

Ahh, yes, if it is multiple vehicles, then I would peg it on being the ground as well.

I know Jenn Grover had a similar problem last year.  It was easily fixed, at a Camping World, but I don't know the details of that fix.

jkjenn

Cyclonic said:

Ahh, yes, if it is multiple vehicles, then I would peg it on being the ground as well.

I know Jenn Grover had a similar problem last year.  It was easily fixed, at a Camping World, but I don't know the details of that fix.

My issue was different, running lights and turned signals didn't work. Check the fuse and then the 7 pin connector on the trailer.

Michigan_Mike

BigMitch said:

Negative battery lead disconnected: 14.5V showing in cabin with TV running (obviously charging)
Negative battery lead reconnected: 12.2V (barely or not charging, battery is at 11.6 or something right now).

Ideas on what to check next?

Have you figured out your electrical problem?  If not I would do as follows:

• Check the fuse at the battery or ensure that you do in fact have a 12 volt dedicated feed line running from the tow vehicle battery back to the female wiring harness at the rear of the TV.  Unless you specify this with the installer, some folks find out later there is no dedicated charge line for the trailer.  
• If so, verify that there is voltage at the female harness port at the rear of the TV.
• With trailer unplugged from all energy sources (e.g., the TV and from shore power), use an LED volt meter and test the 12 v DC inside the trailer and write down the voltage read.  
• Plug the trailer wiring harness into your TV, start vehicle up and test/record the voltage once again inside the trailer.  Your LED volt meter should read a significantly higher voltage while the vehicle is running and if so, this would indicate that the TV is charging the battery.  
• One additional tip would be to install a battery shutoff switch for your trailer battery.  This will help eliminate any parasitic drain on the battery from things like LED circuitry and any other 12 volt DC components that suck up energy while the trailer is parked and sitting idle.  If a shutoff switch is installed you should also take the time to charge up the trailer battery before letting the unit sit idle and either (a) use a battery tender during the off season or (b) periodically check the battery voltage and charge it for 2-3 day periods via the electric converter inside the trailer.  
• And if you haven't taken the battery out and had it properly tested, take it up to a local AutoZone store or local auto parts store and let them test/check the battery for you.  If you have a sealed AGM style battery and it refuses to take a charge, look at the video in the "Video & Resource" discussion area as there is a way to trick the battery into taking a charge.  

Good luck and let us know what you find!  

jkjenn

Here is another thought. Are you running your fridge on battery while connected to the TV? What is the Ah rating of your TV alternator? My Jeep wrangler did not do a great job of keeping the T@b charged while towing. With my new battery meter and battery set up on my T@b I will better be able to monitor it, but before I upgraded the battery, I couldn't leave the fridge on battery for more than a couple of hours without running down the battery. The draw from the fridge was just too great.

skwhee

t@bnero We had that same thing with both a GM and our Ford F150. Charging wire connected at the 7 pin socket, but not attached in the engine compartment(GM) or missing the relay(Ford).
It is our understanding that this is the standard from the factory per both our RV dealer and our Ford dealer.

Michigan_Mike

I had to run a dedicated feed back to the receiver from the battery on my Chevy Equinox but the initial wiring harness hook-up was done as part of my car purchase.  I did the work after the purchase and finding out there was no 12 volt dedicated feed for the trailer.  

RZRBUG

My 2012 GMC came with the towing package and all the wiring was there, but I discovered that the connection had never been made under the dash.  It's a matter of tracing out the wiring to make sure all connections have been made and fuses are all good.  Does not make sense to me that they would install everything but leave it disconnected, but as skwhee says, that is apparently standard practice.

Tenacity

From one newbie to any others that might be out there: TV means Tow Vehicle (not television). You’re welcome.