Help with trailer plug....

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Jan 4, 2010 | 03:23 PM

#16

RV_Tech

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Joined: Jan 2010

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From: Bristol, TN.

I was reading this over and suspect most of you already know this, but you can get a $30.00 seven pin tester with lights that shows you instantly if there is a problem at most automotive stores. Poor grounds are the problem in most cases I see, although I periodically see some really interesting attempts to spice the seven pin cord to the trailer, after its been severed.

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Jan 13, 2010 | 09:14 PM

#17

Vinford

Cargo Master

Joined: Aug 2004

Posts: 3,455

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From: Williams Lake B.C.

Quote:

Originally Posted by TexasRebel

There are fuses under the hood of an '01 F450... why would that have changed in '02?

I dont know why that would have changed .................but it did!

Im having a similar problem but half my lights work and half dont.
Is there more than 1 fuse for The trailer plug?

Jan 14, 2010 | 05:36 PM

#18

cdrmotorsports

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Joined: Aug 2005

Posts: 2,992

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From: Lancaster, MA

Yes there are many fuses for the trailer plug (round and flat plugs). There will be one for all the running lights, one for the left turn (left brake), and right turn (right brake). Those will be both for the 7 round plug and the 4 flat plug. Then for the 7 round only you will find one for the electric brake controller and one for the positive 12 volt power that runs back to the plug. Those are all I can remeber off the top of my head. I don't think there are any others. In owner's manual (and only in the owner's manual) it explains where all the fuses are locacted. They are not listed on the fuse box or anything. Kinf of dumb IMO.

Feb 22, 2010 | 10:28 AM

#19

captbo

Junior User

Joined: Dec 2000

Posts: 69

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From: along the chesapeake Bay

well Thanks this helps

I have an issue with the flat four plug on my 04 F350 s/d crew, I used a multi tester ands I have brake/ flashers and turns but no power on the running light curcuit

I also check the trailer for contiuity on the flat four and it was good! so I guess I am looking under the hood for a fuse !

Feb 22, 2010 | 01:40 PM

#20

BPofMD

FTE Legend

Joined: Jul 2005

Posts: 65,938

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From: Millersville, MD

captbo, I too would open up the 7 pin connector and make SURE that inside isn't full of corrosion like above......The 4 pin gets it's power from the same place....

Feb 22, 2010 | 01:53 PM

#21

captbo

Junior User

Joined: Dec 2000

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From: along the chesapeake Bay

Thanks I will check that!

Feb 22, 2010 | 04:03 PM

#22

87mh

Senior User

Joined: Dec 2008

Posts: 121

Likes: 1

From: In the Airstream

Trailer Fuses???

SOME brands of Travel Trailers also have a chassis fuse panel within the interior of the trailer for extra protection of some of the chassis circuits.

There is always a possibility of one of the chassis fuses being blown, or, especially on older trailers, a problem with the fuse board holding the individual fuses.

Checking the trailer fuse panel may be quicker than checking the trailer plug - depending which is easier to get to.

Feb 23, 2010 | 04:09 PM

#23

Mud-and-Guts

Senior User

Joined: Dec 2009

Posts: 234

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Quote:

Originally Posted by cdrmotorsports

Have you checked your trailer plug with a test light to make sure it has power? Is it a 4 flat or a 7 round trailer plug? I'd assume it's a 7 round because you are talking about a brake controller as well. If you are getting power there then the problem is on the trailer. Like others have said make sure you check the under the hood fuses near the mster cylinder. Brake lights and turn signals run on the same fuses (one for the left side and one for the ride side). The parking lights are on a seperate fuse as well. It could be as simple as corrosion in the plug. Make sure you clean the terminals out really well with a good contact cleaner. Corrosion could also make your brake controller act up as well because it won't be getting a full contact.

much thanks you just answered my question.... My left turn signal and brake light do not work on my trailer.... sounds like i need to check the fuses... much thanks...