trailer wire problem
Thread Starter
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Mountain Pass
Joined: Sep 2007
Posts: 151
Likes: 3
trailer wire problem
my right trailer stop light has been stuck on for a couple weeks now.
when i disconnect trailer from truck, there is still power in the
trucks trailer connector, with truck on or off.
its 05 f350 with tow command
any ideas what to do?
thanks
when i disconnect trailer from truck, there is still power in the
trucks trailer connector, with truck on or off.
its 05 f350 with tow command
any ideas what to do?
thanks
Elder User
Joined: Aug 2004
Posts: 602
Likes: 1
From: Sacramento, CA.
Do all of the other lights work as should ? Are you using a factory installed trailer connecter ? Have you added any other accessories to your truck ? Cant imagine how all of sudden you got constant power to only one brake light. I could see it if they were both staying on.(Brake light switch) Does the left brake light work as should? good luck.
Post Fiend
Joined: Mar 2007
Posts: 26,966
Likes: 50
From: Texas
Welcome to the site.
Which type of plug are you using? The brown wire should control the running lights, and yellow and green control the turn. A combination controls your brake lights. The plug on the back of the truck will have power to it whether a trailer is hooked up of not.
If you want to isolate the problem trying hooking up to a different trailer, or have someone else hook up to your trailer and see if the problem is duplicated. If you can't do that you could always switch the position of the yellow & green wire so and see if the problem shows up in your left signal.
Which type of plug are you using? The brown wire should control the running lights, and yellow and green control the turn. A combination controls your brake lights. The plug on the back of the truck will have power to it whether a trailer is hooked up of not.
If you want to isolate the problem trying hooking up to a different trailer, or have someone else hook up to your trailer and see if the problem is duplicated. If you can't do that you could always switch the position of the yellow & green wire so and see if the problem shows up in your left signal.
Senior User
Joined: Jul 2006
Posts: 234
Likes: 0
From: Texas
F350-6 is correct in that the plug will have power on it at all times IF a turn, brake, running lamp are selected in the cab. with truck off and no lights or brakes i dont think there should be any power to the plug. the only power to the plugs on my 04 with tow package is trailer power with truck running. 04 wire bundle comes from rear of truck along frame rail up into the engine compartment below master cylinder to a connector. from there thru the firwall to inside truck. disconnect under the hood and check for voltage.
sorry i dont have a diagram of an 05 and i am not familiar with tow command. are there any relays in fuse block dealing with trailer brakes? if so pull it and see what happens.
good luck
sorry i dont have a diagram of an 05 and i am not familiar with tow command. are there any relays in fuse block dealing with trailer brakes? if so pull it and see what happens.
good luck
Thread Starter
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Mountain Pass
Joined: Sep 2007
Posts: 151
Likes: 3
everything has worked fine for 2 years now with the same truck and
trailer, the trailer lights work fine on my other truck. so its narrowed down to
the f350. all the other lights work fine, just the right side stop light is stuck on all the time while connected to the truck. I have already checked the two connectors on the truck and they are both clean and corrosion free.
how do you reset the tow command system? or is that even possible?
thanks
Josh
It has to go in for a leaking front axle , so i guess ill have the dealer check it out then, just sux cause i trailer every day.
trailer, the trailer lights work fine on my other truck. so its narrowed down to
the f350. all the other lights work fine, just the right side stop light is stuck on all the time while connected to the truck. I have already checked the two connectors on the truck and they are both clean and corrosion free.
how do you reset the tow command system? or is that even possible?
thanks
Josh
It has to go in for a leaking front axle , so i guess ill have the dealer check it out then, just sux cause i trailer every day.
Senior User
Joined: Jul 2005
Posts: 113
Likes: 0
From: Lake Worth, Fla.
I have the same problem on my 2000 F350 what's up with that. I hope I can catch the next thread. So I can figure out what's wrong with mine.
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Senior User
Joined: Jul 2006
Posts: 234
Likes: 0
From: Texas
is there a relay for your tow command? cb? and i agree if you are unhooked from trailer and getting voltage on the right turn/brake with truck not running it is a truck fault. r u using the 7 way or 4 way plug?
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Thread Starter
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Mountain Pass
Joined: Sep 2007
Posts: 151
Likes: 3
i use the big round seven pin plug
I checked both plugs with a multimeter and
both have constant power on that wire.( i think there piggybacked anyway)
good idea on the relay, i looked in the owners manual and couldnt find anything
about any relays. but maybe ill just start pulling them out from under hood , one at a time and give each one a couple taps and retry it.
thanks
Josh
I checked both plugs with a multimeter and
both have constant power on that wire.( i think there piggybacked anyway)
good idea on the relay, i looked in the owners manual and couldnt find anything
about any relays. but maybe ill just start pulling them out from under hood , one at a time and give each one a couple taps and retry it.
thanks
Josh
Senior User
Joined: Jul 2006
Posts: 234
Likes: 0
From: Texas
again i am not so sure on your year truck, but you have some relays in the fuse block and under the hood and and on my 04 there are what ford calls "unserviceable" relays which seem to be intergral to the central junction bo
fuse panel). then there are a few relays under the dash that you wont find in the manual.
pull relays and then check voltage.
and yes both plugs are feed from the same harness, which comes from the connector under the hood on the drivers fender well. i would find that connector on your truck, disconnect it and see if voltage is present at the plug. this rules out a short from the firwall back.
you might want to place this thread in the electrical /wiring problems a little further down the forum page. maybe someone there has a wiring diagram for your truck and could tell us where the right turn/brake get power.
fuse panel). then there are a few relays under the dash that you wont find in the manual. pull relays and then check voltage.
and yes both plugs are feed from the same harness, which comes from the connector under the hood on the drivers fender well. i would find that connector on your truck, disconnect it and see if voltage is present at the plug. this rules out a short from the firwall back.
you might want to place this thread in the electrical /wiring problems a little further down the forum page. maybe someone there has a wiring diagram for your truck and could tell us where the right turn/brake get power.
Last edited by flyinnuts; Oct 8, 2007 at 08:33 AM.
Thread Starter
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Mountain Pass
Joined: Sep 2007
Posts: 151
Likes: 3
i think i traced it to a sticky relay under the hood. seems when the truck heats up under the hood it starts to stick. so i swapped the relays for the right and left
side trailer lights. so ill see if the other side sticks on tomorrow.
thanks
Josh
side trailer lights. so ill see if the other side sticks on tomorrow.
thanks
Josh