Separate fuses for trailer plug??
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Cross-Country
Joined: Mar 2004
Posts: 67
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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...
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...
Postmaster
Joined: Jul 2015
Posts: 4,392
Likes: 22
From: very South Texas
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.
Hotshot
Joined: Jan 2004
Posts: 19,768
Likes: 1,082
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.
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.
Hotshot
Joined: Jul 2013
Posts: 14,307
Likes: 2,198
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.
star lock washers between grounds and the frames will help.
my bet is you have a ground problem.
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.
Check all connections at the trailer connector, they can loosen.
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Hotshot
Joined: Jan 2004
Posts: 19,768
Likes: 1,082
From: St Louis
Please explain the logic of how a bad battery (out of two in parallel), would affect ONLY the trailer running lights.
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