no power from 7 way plug?

dennis b · 03-12-2015, 06:48 PM

So I went to hookup new to me TV to trailer and had no lights.
I jumped #4 12v on plug to #3 taillights on plug and had nothing.
Checked fuse and connections, all good. Changed fuse anyway.

What am I missing?

Paintinfool3 · 03-12-2015, 06:54 PM

did you test the truck plug to a good ground and make sure it was good on the truck side ... then I would check the ground on the trailer ... no lights usually means no ground

dennis b · 03-12-2015, 07:01 PM

Ground is good from what I see

Paintinfool3 · 03-12-2015, 07:05 PM

well you would think it would carry through the hitch also but just a thought ... seems weird no lights , what about turn signals

Bassdogs · 03-12-2015, 07:15 PM

put a meter on the tv socket and make sure you are getting power at the bumper socket. If yes, and you've got nothing on the trailer, your problem is most likely a ground. Had this problem on my trip home from the gulf last week. Had to make an emergency stop at a very kind rv dealer who found the problem almost immediately. There should be a junction box under the tongue frame where the pigtail connects to the tt wiring. Looks just like a typical electric junction box because that is what it is. Remove the cover and inside will be a lot of wires where the power from the tv is connected to the trailer lites. Mine had plastic twist caps connecting wires to the tail lites, marker lites, etc. There most likely is a large bundle of white wires [not sure why there are so many] connected by one twist on cap. Too many wires in my mind to get a reliable connection for the ground. When the tech fiddled with the ground bundle the lites all popped on. He secured the grounds and connected one of them with a self tapping screw to the back of the junction box. Betting you'll find your problem in the same place.

Tharrison · 03-12-2015, 07:20 PM

Often the fuse to the plug is not installed from the factory.

ninjahbob · 03-12-2015, 07:20 PM

Bassdogs advice is right on. If not let us know.

dennis b · 03-12-2015, 07:39 PM

Quote:

Originally Posted by Paintinfool3

well you would think it would carry through the hitch also but just a thought ... seems weird no lights , what about turn signals

no turn signals either!

dennis b · 03-12-2015, 07:40 PM

Quote:

Originally Posted by Tharrison

Often the fuse to the plug is not installed from the factory.

Did I not ay that I replaced fuse?

dennis b · 03-12-2015, 07:44 PM

Quote:

Originally Posted by Paintinfool3

well you would think it would carry through the hitch also but just a thought ... seems weird no lights , what about turn signals

Not concerned right now about TV just trailer plug which is hooked up to good battery

dennis b · 03-12-2015, 08:33 PM

Problem seems to be between plug and trailer battery

eldermike · 03-13-2015, 04:15 AM

You will find the bad ground either in the box already mentioned or in some cases that bundle of grounds has a single pigtail that connects to the frame somwhere close to your ball on the A frame. Electrolysis always eats that type connection up.

RoyBraddy · 03-13-2015, 05:46 AM

I carry one of these 7-way Trailer adapter n RV TOOL BOX that takes the guessing out of what is at fault. The TRUCK SIDE or the TRAILER SIDE... Got mine from AMAZON...

When I got my 2010 FORD Truck it has an unmarked envelope in the glove box that had a 12VDC FUSE and RELAY. Finally figured out these were for the TRAILER TOW connector. The FUSE and RELAY had to be installed in the TRUCK FUSE panel The 12VDC would only be ON when the truck ignition key was ON. My truck also had individual fuses for the DOT Safety lights.

This did not however affect the DOT safety lights - Only the truck 12VDC charge voltage for the trailer battery.

Roy Ken

Bassdogs · 03-13-2015, 08:06 AM

Quote:

Originally Posted by dennis b

Not concerned right now about TV just trailer plug which is hooked up to good battery

If the TT is not on the ball, you do not have a ground. Hook the TT to the TV after confirming that you have power at the socket. Center post on the TV socket is the ground. Other ports are for tail lites, turn, marker lites and brakes. If no power thru the socket, you have a problem somewhere on the TV. If yes, see my previous post and check in the junction box.

Problem solving is a series of steps that isolate the problem. By learning what it is and what it isn't and by going step by step thru the system you will eventually find the fault.

Bassdogs · 03-13-2015, 08:10 AM

If the "good" battery you mention is the TT house battery, that battery has nothing to do with your TT nav lites. Why are you avoiding hooking up to the TV?

DocBrown · 03-13-2015, 08:56 AM

Quote:

Originally Posted by Bassdogs

If the TT is not on the ball, you do not have a ground.

X2! I learned this the hard way many years ago when I had a pop-up. I was going through the same thing as the OP, when all I had to do was hook up like I was ready to travel, and guess what? Everything worked fine.

DocBrown · 03-13-2015, 08:58 AM

Here's a link to Roy's nifty tester!

dennis b · 03-13-2015, 10:33 AM

PROBLEM FOUND!!!!!!!!!!!!!!!!!!!!!!!!!

Fuse socket not making good connection!

Thanks to all that responded! I gotta put Roy's tester on my want list.

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