7 pin trailer problems
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Freshman User
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7 pin trailer problems
I tried posting this problem twice in the "11-16" Super Duty forum with no takers? 1st it's a 2014 F250 Super Duty 6.7 4WD crew cab SRW with the factory tow package. I've never towed anything with this truck (bought it last fall) decided to check the 7pin-4pin outlets (plug) and it was corroded beyond use proceeded to remove it noticed plug (vehicle) side was also beyond use, cut it off bared wires checked ground it was good. all I had was a 12v positive (orange/red) nothing else proceeded to owners manual check fuses found both RH & LH 30amp cartridge fuses blown and replaced them, now I have turn signals, brake, and hazard lighting. I also have the backup light (grey) wire is hot when in reverse. I have everything but running lights / parking lamps (brown) I've checked and re-checked fuses, relays and the fuse in the kick panel fuse box (interior) nothing absolutely nothing! Please HELP! it's driving me nuts. Thank You
Postmaster
Joined: Jul 2015
Posts: 4,392
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From: very South Texas
several trailer fuses under the hood.. fuse box..
12 volt power
running lights
left turn
right turn.
I made a tight "U" turn with trailer. pinched cable. took out all 4 fuses.... all under hood... bad thing.. 3 auto part stores to get 4 fuses..
12 volt power
running lights
left turn
right turn.
I made a tight "U" turn with trailer. pinched cable. took out all 4 fuses.... all under hood... bad thing.. 3 auto part stores to get 4 fuses..
Hotshot
Joined: Oct 2015
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From: Wyoming
Ouch! I'll have to keep that in mind.
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Freshman User
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Re: wiring problems 7 pin
Yes I've checked the fuses and relays in the power distribution box under the hood. No power for the parking-running lights in the 7pin plug wiring harness (plug is junk it has been discarded). The running lights and every light works on the truck as it is supposed to. I don't know if the trailer brake controller works or not? Is there a way to check it without hooking a trailer up to it? The trailer hasn't been unpacked from winter storage yet. I also checked no.30 fuse in the kick panel and it is good also. Every wire that goes into the 7pin plug has power except (white) ground (and it is good) and the brown (running lights) has nothing (no power) I do appreciate your guidance with this problem.
Super Moderator
Joined: Aug 2008
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From: Frederick, MD
to test the TBC just push the slider. Should not have any faults come up.
just trailer disconnected.
That should be good.
For this wiring issue it would appear you are going to have to trace that brown wire.
So lets go back to the next connection point and pull that apart and see if you have power there. It should be easy enough since you have cut the 7 pin off and just have the harness in hand.
So test/look at that next connection in line and see if you can determine if the brown has power there.
just trailer disconnected.
That should be good.
For this wiring issue it would appear you are going to have to trace that brown wire.
So lets go back to the next connection point and pull that apart and see if you have power there. It should be easy enough since you have cut the 7 pin off and just have the harness in hand.
So test/look at that next connection in line and see if you can determine if the brown has power there.
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Laughing Gas
Joined: May 2007
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Am with Senix to trace the brown wire.
It is likely the brown wire from the 7 pin goes to a 'T' connector inline with the truck's tail lights. Just as likely is that the brown wire follows the same path as the stop and turn wires as part of a 4 wire bundle. Presuming so, my vote is to focus on whether the brown wire was cut between the 7 pin and 'T' or that the junction in the 'T' broke. Hopefully there is no creative wiring to figure / sort out.
It is likely the brown wire from the 7 pin goes to a 'T' connector inline with the truck's tail lights. Just as likely is that the brown wire follows the same path as the stop and turn wires as part of a 4 wire bundle. Presuming so, my vote is to focus on whether the brown wire was cut between the 7 pin and 'T' or that the junction in the 'T' broke. Hopefully there is no creative wiring to figure / sort out.
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Postmaster
Joined: Jul 2015
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From: very South Texas
if my memory is correct... the next 7 pin connector.. is at the front of the BED.. below next to frame... for ( IF ) 5th wheel setup..
USE a 12 volt test light.. not a volt meter for best results. my opinion..
also see of there is power AT THE FUSE.. both sides. again using test light.
USE a 12 volt test light.. not a volt meter for best results. my opinion..
also see of there is power AT THE FUSE.. both sides. again using test light.
Mountain Pass
Joined: Oct 2015
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I'm curious as to why you guys are recommending test lights instead of using a DMM?
In the book AUTOMOTIVE WIRING AND ELECTRICAL SYSTEMS, the author says: "old school incandescent test lights have no place in the modern automobile because they have very low impedance. I won't even check fuses with them - just too many horror stories that resulted in someone spending their hard-earned money to fix a problem that could have been easily avoided."
In another area he says: "The 'test light' has very low resistance between it's ground clip and probe tip - low enough to deploy an airbag in the event you're probing around in the wrong area by accident."
There are computer safe test lights these days, but a DMM - which I already have - is equally safe. What advantage would there be in acquiring one of these new, "safe" test lights?
In the book AUTOMOTIVE WIRING AND ELECTRICAL SYSTEMS, the author says: "old school incandescent test lights have no place in the modern automobile because they have very low impedance. I won't even check fuses with them - just too many horror stories that resulted in someone spending their hard-earned money to fix a problem that could have been easily avoided."
In another area he says: "The 'test light' has very low resistance between it's ground clip and probe tip - low enough to deploy an airbag in the event you're probing around in the wrong area by accident."
There are computer safe test lights these days, but a DMM - which I already have - is equally safe. What advantage would there be in acquiring one of these new, "safe" test lights?
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Just my two cents: I grew up using multimeters for everything, but recently have started using test lights. I have found myself confused on several occasions by the results from a multi-meter. The most common problem is that the multi meter will show voltage on a corroded or almost severed wire or other bad connection, without warning you that there's very little current-caring capacity. An incandescent test light will light up more or less brightly, showing you that while you may have current, you have a bad connection somewhere.
I had not considered the dangers of using a test light with today's computer controlled vehicle systems. I did accidentally set off the theft protection on my 07 Chevy Cobalt when looking around with a multi meter installing cruise control. Dealer has to reset it while they were activating the cruise.
On a related note, the incandescent test lights and the LED ones have different purposes. I don't think the LED versions draw enough current to earn about poor connections. But i did learn that you can check the very short ignition signal (the one that trips the coil) on a 4-wheeler with them, whereas the incandescent version and multi meter neither one react fast enough.
I had not considered the dangers of using a test light with today's computer controlled vehicle systems. I did accidentally set off the theft protection on my 07 Chevy Cobalt when looking around with a multi meter installing cruise control. Dealer has to reset it while they were activating the cruise.
On a related note, the incandescent test lights and the LED ones have different purposes. I don't think the LED versions draw enough current to earn about poor connections. But i did learn that you can check the very short ignition signal (the one that trips the coil) on a 4-wheeler with them, whereas the incandescent version and multi meter neither one react fast enough.
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