Hi all,
I have a 2006 f350 hooked up my trailer and the trailer tail lights worked for 3 minutes then went out. Checked the fuse (#38) it tests good. Checked voltage at both the 4 position and 7 position plug and no 12v. Read a bunch of forum posts and found that the problem may be in a mystery relay in the fuse box. I called a fuse box refurbisher and he told me that he had never heard of that and if i sent my fuse box to him he would not know how to test for it. I called another company and got the same story. I very close to simply running a fused 12v off one of my switches on the dash, however, I thought i would check here first
any help will be greatly appreciated, this makes no sense.

 

Fuse 38 is the fuse that provides power to activate the relay, but not the fuse that provides the power to the trailer lights. That is fuse #17, but that fuse can be verified good if you have power to parking, rear, and license lamps. Do you have power to these other lights?

The trailer tow relay is integral to the Central Junction Box (which is the main fuse box under the dash on the drivers side). It is not serviceable. This relay does not go out very often, it is usually the integral relay for the fuel pump that causes most people to have the CJB repaired.

When my fuel pump relay failed, I just installed an external (separate) relay to the fuel pump circuit (prior to the inertia switch). I activated it with the same ground from the PCM that activated the original relay. I wanted all of the OEM safety features built into the fuel pump operation. If you are going to run an external relay, you would probably want to do something similar (ie tie into the same circuits that activate the relay for any external relay you added).

Before any of that, verify it isn't a broken wire or two.

 

Responded to your PM

 

Status? It is helpful for potentially a lot of folks to have closure on these threads.

 

I believe bismic has brought up a good point.
Most of us are here to share our experience and knowledge AND keep up to date with learning.
Please, Hayapower, can we improve the forum's effectiveness and share the family knowledge, thanks.

 

Thanks Hanky.

The 6.0L community is down to only 2 active forums (for all practical purposes). I hate to see other forums dwindling also.

 

From where I sit/stand, this forum is alive and well.
We had lots of latitude to do many different things with vehicles , in the past.
Progress has clipped our wings, so to speak, and the usual fixes cannot always be used or effective.
So what do we do?
We come here ask questions and hopefully someone will come up with the right answer.
There are a lot of folks that have very little automotive experience /knowledge and we try to share some ,hopefully useful, knowledge to assist them with their concerns.
I for one, have learned a lot just reading the posts from folks that had the right answers.
When we decide we know all the answers and don't need to continue learning, look out, we are headed for trouble.
Thanks for participating and allowing me to participate. Trying to find answers forces me to learn and do research so I might contribute something worthwhile.

 

Totally agree. There are probably 4 or so regulars on this particular sub forum (just looking back on past threads). That works pretty well. Hopefully the regulars keep participating for a good long time (that would be good for a couple of reasons!). Lots of opportunities for everyone to learn.