Bumper pull trailer hook up strangeness

[Farmer 5500]

Bought a light duty 20’ bumper pull trailer for mowers & ATV’s yesterday.
At dealer, trailer battery was dead. Dealer stole a battery from trailer next to it. We verified with a tester it was healthy.
Drove 90 miles home. Now I’m pretty sure when my big gooseneck is hooked up, there’s a little trailer icon on the cluster? Sorry, it’s been a few months since I had it connected and I can’t remember.
But when I hook up the new bumper pull to tow it home last night, no trailer icon light.

Get home, disconnect trailer and put truck in garage.

Hook up trailer this morning and push battery test light-battery says its dead. Hook trailer up to tow with it and everything is working fine.
Get back to shop in a few hours and battery tests fine.
Disconnect trailer and I get the disconnected trailer icon on the dash.

Is my trailer plug down on bumper not charging the battery? Is there an icon supposed to be on when trailer plug is connected?
I notice my GN trailer seems to go through a battery per year, too and thought that was very excessive.

 

[Ostracize]

I'd check the trailers ground circuit.

 

[Farmer 5500]

I'd check the trailers ground circuit.

You are talking about checking the wiring ground to the trailers chassis for rust/corrosion?

 

[Ostracize]

Yessir.. Basically tracing and checking all ground connections and checking for continuity across the conductors

 

[Farmer 5500]

Do you have a small trailer icon on your dash with trailer hooked up? I could go hook up my GN to find out, but it’s 10 miles away and much easier to ask another Ram owner

 

[Ostracize]

I do... But I believe(don't take as gospel) that light is for the trailer blind spot monitor... But it's possible it's for both or operates slightly different if you don't have the TBMS

 

[Ostracize]

To clarify... I've actually had the trailer light / length of trailer light up when I wasn't hooked up to a thing cause someone was following me out of a parking lot super close and I think it tricked the sensors in the brake lights

 

[Ostracize]

 

[jebruns]

If the new trailer has a 7 pin plug and you have 12v on the bumper at the pin in your picture above, the problem has to be on the trailer end (assuming ground it good, as mentioned above).

 

[H3LZSN1P3R]

Does the trailer have brakes? If not the truck wont show anything on the dash when connected as the only way it knows its there is by the resistance of the brake wiring

 

[Farmer 5500]

Yes it has brakes on one axle. They respond to both the manual and service brakes.
No trailer icon on dash when plugged-in. But warning light comes on when plug is pulled out.

Other information: trailer sat outside a while and battery was DOA when I bought it. Wonder if theres a rusted ground wire?

 

[AH64ID]

No light under normal operation. It will show a trailer with a line thru it if you disconnect the trailer with the ignition on.

 

[Farmer 5500]

OK, thanks. I think I remember my Duramax 3500 having one when trailer plugged in
I swore my GN has a light on when plugged in…..oh well. That’s kind of a relief. I thought something was broke.