Information for owners of Ford trucks 2004-2010.

I just had a very frustrating week of trying to repair my trailer marker lights on my 2007 F-350

My wife had helped me hook up a dump trailer and she miss aligned the trailer hook up and forced the 7 pin into the socket on the truck.

This never blew any fuses but did blow out the "Trailer Marker Lamp Relay" This relay is hardwired onto the computer board of the interior fuse box and is not seviceable separately. You must replace the entire interior fuse box assembly to repair it.

Fuse #38 20 amp runs two relays on the board. 1-Trailer marker lamp relay, 2-Trailer Backup Relay.

If you have no wiring issues and fuse #38 is good than you will have to replace the fuse box assembly to solve a Trailer Marker lamp relay problem. It cost me $285.00 for a new fuse box and solved my issue.

This was finally confirmed by the the only dealership out of 5 that would help me. It took them 3 days of contacting Ford to get an answer to the location of the trailer marker lamp relay. It is 100% part of the computer board and can not be replaced separately on 2004-2010 trucks.

This schematic should help; https://www.fleet.ford.com/truckbbas...bb_pdf/273.pdf

 

So what you're saying is, never let the wife hook up your trailer!

 

Absolutely correct!!!

Very expensive and stressful help.

 

Knew there was a reason I always cranked the trailer up high when hooking up
cheaper to replace a dented up License Plate.

Edit
guess this would not work on a lifted truck

 

i have the exact opposite problem. have parking lamps but no brake/blinker to the trailer

 

If your truck is between 2005-2007 that should be an easy fix.

If fuses are ok, relay numbers 201 & 202 under the hood fuse block control turn and stop for trailer lights.
Ford part Number F5TZ-14N089-B Relay 414066 $20.00 each

 

Your advice is very good, but please keep in mine that different model years had different fuse panel arrangements. 2002-2004 trucks don't have a fuse block under the hood.

As near as I can tell, 1999-2001 were pretty much the same. 2002-2004 did away with the underhood Power Distribution box. It was reintroduced for the 2005-2007 models, which were all pretty much the same. In 2008 the interior fuse panel changed significantly and I have no idea what they did in 2011.

Often times we think in terms of the truck we own and are familiar with and forget that things changed over time. I've gotten caught doing this myself more than a few times.

I can say for sure from experience and my 2004 service manual, that the trailer tow park lamp relay IS a fixed part of the CJB (really stupid as far as I'm concerned). But the turn/stop relays are in an auxiliary relay box under the hood and the battery charge relay is a standard mini-ISO replaceable relay in the CJB.

P.S, on edit: The trailer backup light relay also appears to be a replaceable relay in the CJB, but it's smaller and I don't know what type it is.

 

Had the exact thing happen to my 2004 about 2 weeks ago. For me it was a blown fuse located in the dash up under the steering wheel. Pretty sure it was fuse # 6, it was a yellow 20 amp mini-fuse.

 

Thank you, I do apologize. The last thing I want to do is spread more misinformation. I will change the years in the post.
Before I purchased a new interior fuse box I tried to find a used one. The dealer told me that all Ford trucks 2004-2010 were the same setup because the part number was the same, that is why I answered the way I did.

And I absolutely agree what a really stupid setup. It is so ridiculous it is very hard to even find help because everyone assumes its a wiring problem. 4 of the 5 dealerships blew me off and said I need all new wiring if the fuse is good. Luck would have it that I found the schematic from Ford that proved there was a relay. So I told them to please order me the relay shown in the schematic that is when they finally figured it out for me.

 

sorry for the hijack, mines a 2002

 

I had the same problem when I got my 2003 a few of years ago. I came off the fuse to a standard relay and ran a wire down under the carpet, and tied it back into the wire going to the running lights. Has worked fine for me for 4 years now. Cost only a few dollars.