Notices
1999 - 2016 Super Duty 1999 to 2016 Ford F250, F350, F450 and F550 Super Duty with diesel V8 and gas V8 and V10 engines
Sponsored by:
Sponsored by: Real Truck

Separate fuses for trailer plug??

Thread Tools
 
Search this Thread
 
Old Aug 25, 2016 | 12:03 PM
  #1  
KMAPRO's Avatar
KMAPRO
Thread Starter
|
Cross-Country
Joined: Mar 2004
Posts: 67
Likes: 0
Separate fuses for trailer plug??

At the risk of sounding like I would be one to fall for the "blinker fluid" or "honk limit" joke....I just have to ask this question because I have never had to deal with this before.....

No matter what trailer I hook up to my truck, I can get brake lights, turn signals and flashers to work without a problem.

However, I can not get running/tail lights to work.

I have checked all of the wiring and it all looks OK. My guess is that it is the plug and that's because I will occasionally get a "beep" and warning that "trailer is disconnected"...even though I know it is.

BUT, someone mentioned something about the trailer hitch having its own separate fuses. I call BS on this, but thought I would ask and sound stupid either way...
 
Reply
Old Aug 25, 2016 | 12:18 PM
  #2  
Sam I Am's Avatar
Sam I Am
Posting Guru
Joined: Jun 2009
Posts: 1,908
Likes: 20
From: Fort Smith, Arkansas
Yes, the power distribution box under the hood contains the trailer relays and fuses.
 
Reply
Old Aug 25, 2016 | 02:26 PM
  #3  
Chuck's First Ford's Avatar
Chuck's First Ford
Postmaster
Joined: Jul 2015
Posts: 4,392
Likes: 22
From: very South Texas
Originally Posted by Sam I Am
Yes, the power distribution box under the hood contains the trailer relays and fuses.

Very True.. and all U.S. brand Trucks..

and has for over 10 years now. maybe 15....

read back of fuse box lid. or owners manual.
 
Reply
Old Aug 25, 2016 | 07:29 PM
  #4  
projectSHO89's Avatar
projectSHO89
Hotshot
20 Year Member
Photogenic
Photoriffic
Shutterbug
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
Unfortunately, you failed to identify what year you're working on, so pinpoint assistance is impossible.

Several years worth of Super Duty models have the trailer [running lamp] relay soldered into the fusebox and the relay replacement is not a simple plug and play.
 
Reply
Old Aug 26, 2016 | 07:06 AM
  #5  
speakerfritz's Avatar
speakerfritz
Hotshot
10 Year Member
Community Builder
Community Influencer
Liked
Joined: Jul 2013
Posts: 14,263
Likes: 2,184
by pass the hitch link for ground purposes and temporaily bolt a wire to the truck frame and the trailer frame....if everything now works trouble shoot all your trailer related grounds.

star lock washers between grounds and the frames will help.

my bet is you have a ground problem.
 
Reply
Old Aug 26, 2016 | 01:58 PM
  #6  
projectSHO89's Avatar
projectSHO89
Hotshot
20 Year Member
Photogenic
Photoriffic
Shutterbug
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
If it was a ground problem, it would affect ALL trailer lighting, not just the running lamps.
 
Reply
Old Aug 26, 2016 | 06:06 PM
  #7  
ligito's Avatar
ligito
Posting Guru
Joined: Nov 2008
Posts: 1,229
Likes: 2
From: Oregon
If you have dual batteries, check that, also, one may be dead.
Check all connections at the trailer connector, they can loosen.
 
Reply
Old Aug 27, 2016 | 07:27 AM
  #8  
projectSHO89's Avatar
projectSHO89
Hotshot
20 Year Member
Photogenic
Photoriffic
Shutterbug
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
Originally Posted by ligito
If you have dual batteries, check that, also, one may be dead.
....
Please explain the logic of how a bad battery (out of two in parallel), would affect ONLY the trailer running lights.
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath

 Verdad Gallardo
story-1

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

 Joe Kucinski
story-2

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

 Brett Foote
story-3

Top 10 Ford Truck Tragedies

 Joe Kucinski
story-4

AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

 Brett Foote
story-5

Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

 Michael S. Palmer
story-6

Ford's 2001 Explorer Sportsman Concept Looks For a New Home

 Verdad Gallardo
story-7

10 Best Ford Truck Engines We Miss the Most!

 Joe Kucinski
story-8

2026 Shelby F-150 Off-Road: Better Than a Raptor R?

 Brett Foote
story-9

2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

 Michael S. Palmer
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
RUSTANG67
2009 - 2014 F150
4
Jul 18, 2015 07:25 PM
3006banger
1999 - 2016 Super Duty
6
Jul 15, 2009 07:56 AM
Ford with onions
1999 - 2016 Super Duty
3
Apr 3, 2009 02:45 PM
wat704
1997 - 2003 F150
4
Feb 28, 2005 10:57 PM
alpine7572
1978 - 1996 Big Bronco
9
Feb 10, 2003 08:20 AM




All times are GMT -5. The time now is 10:09 PM.

story-0
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-05-30 18:33:59


VIEW MORE
story-1
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-2
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-3
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE
story-4
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

And it might be even better than that.

By Brett Foote | 2026-05-18 19:26:42


VIEW MORE
story-5
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Slideshow: Does lowering an F-150 Lobo RUIN the ride quality?

By Michael S. Palmer | 2026-05-18 19:20:37


VIEW MORE
story-6
Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Slideshow: Ford's bizarre fishing-themed Explorer concept has resurfaced after spending decades largely forgotten.

By Verdad Gallardo | 2026-05-12 18:07:46


VIEW MORE
story-7
10 Best Ford Truck Engines We Miss the Most!

Slideshow: The 10 best Ford truck engines we miss the most.

By Joe Kucinski | 2026-05-12 13:09:47


VIEW MORE
story-8
2026 Shelby F-150 Off-Road: Better Than a Raptor R?

Slideshow: first look at the 810 hp 2026 Shelby F-150 Off-Road!

By Brett Foote | 2026-05-12 12:50:07


VIEW MORE
story-9
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

Slideshow: Everything You Need to Know about the 2027 Super Duty Carhartt Package!

By Michael S. Palmer | 2026-05-07 17:51:06


VIEW MORE