Hooking up a plug for trailer lights?
Thread Starter
|
Senior User
Joined: Jun 2007
Posts: 349
Likes: 0
Hooking up a plug for trailer lights?
Looking for some help with wiring a trailer light plug.
I have a 1975 F250 that I will be using to tow my boat. I recently finished installing a completely new wiring harness from bumper to bumper. My boat has a 6 wire round connector and so does the truck.
My questions:
1) Since the wires from my new harness are labeled, can I simply splice into the wires for right turn, left turn, brake and tail and match them up to the plug wires that correspond to these on the trailer?
2) I recall that the flashers seem to flash faster when the trailer lights are hooked up. Is there a better flasher that is recommended to eliminate this?
Gotta get my boat on the water!
Thanks.
I have a 1975 F250 that I will be using to tow my boat. I recently finished installing a completely new wiring harness from bumper to bumper. My boat has a 6 wire round connector and so does the truck.
My questions:
1) Since the wires from my new harness are labeled, can I simply splice into the wires for right turn, left turn, brake and tail and match them up to the plug wires that correspond to these on the trailer?
2) I recall that the flashers seem to flash faster when the trailer lights are hooked up. Is there a better flasher that is recommended to eliminate this?
Gotta get my boat on the water!
Thanks.
Lead Driver
Joined: Mar 2010
Posts: 5,250
Likes: 11
From: West Virginia
For your first question, it depends on how your trailer is wired. I am not familiar with the older 6 pin connectors and have never used one or wired a trailer with one, but I doubt they are that different than the newer style ones. If you have separate tail lights and turn signals then you would be fine to go ahead and wire them up wire for wire. If, like most modern trailers, you have a "stop/turn" as they call it, which is where you have only 2 lights on the rear and they are both dual filament, and one filament is the running lights, and then a second filament is both the brake light AND the turn signal, then you will need a controller. I guess its theoretically possible that your trailer would already have one integrated into the wiring, but I've never seen one that way. Usually the stop turn controller is behind the plug on the truck. The stop turn controller should have a resistor in it that would keep your turn signals from blinking too fast as well.
Posting Guru
Joined: Jul 2011
Posts: 2,104
Likes: 0
From: Virginia Beach, VA
Posting Guru
Joined: Sep 2009
Posts: 1,159
Likes: 1
From: Suburbs of Chicago
Yes you can splice, only if you have the old separate trailer lights like hasteranger said. However you do it, PLEASE DON'T USE SCOTCHLOCKS. Do it right, use butt connectors or solder that ish in there. Scotchlocks are gonna corrode on you in like a year if you live where they salt the roads. And you would be totally ruining that new harness that you just put in.
2) You need another resistor, like hasteranger said. The reason it blinks faster is because you have created a parallel circuit, decreasing total circuit resistance and increasing total circuit amperage. This is the same thing that happens when a blinker goes out, your blinkers blink faster because one of the filaments is burned out, and there's less total resistance.
2) You need another resistor, like hasteranger said. The reason it blinks faster is because you have created a parallel circuit, decreasing total circuit resistance and increasing total circuit amperage. This is the same thing that happens when a blinker goes out, your blinkers blink faster because one of the filaments is burned out, and there's less total resistance.
Moderator
Joined: Jul 2011
Posts: 6,515
Likes: 671
From: Sioux Falls Area
maybe i got it wrong, but doesnt a 75 just have a stop/turn in the rear?
that is to say the same bulb is the running/stop and it just blinks for the turn signal.
i know my 79 is set up this way for sure. if that is the case, just splice into the circut to make the connection. the trailer lights will do the exact same thing that the truck lights do.
if not and you have separate brake and turn lights on the truck, then you will either need a converter, or i could tell you how to do it with two relays, but the converter would be much easier.
if your flasher is going bonkers with the trailer hooked up, just get an electronic flasher. any parts store should have one. the electronic flasher controlls the flash cycle electricly instead of thermo-mechanically. It will just flash at a set rate regardless of the electrical load on the flasher. should only cost 10-15 bucks for the flasher unit. Had to do the same thing in my Crown-Vic ... worked like a charm.
that is to say the same bulb is the running/stop and it just blinks for the turn signal.
i know my 79 is set up this way for sure. if that is the case, just splice into the circut to make the connection. the trailer lights will do the exact same thing that the truck lights do.
if not and you have separate brake and turn lights on the truck, then you will either need a converter, or i could tell you how to do it with two relays, but the converter would be much easier.
if your flasher is going bonkers with the trailer hooked up, just get an electronic flasher. any parts store should have one. the electronic flasher controlls the flash cycle electricly instead of thermo-mechanically. It will just flash at a set rate regardless of the electrical load on the flasher. should only cost 10-15 bucks for the flasher unit. Had to do the same thing in my Crown-Vic ... worked like a charm.
Thread Starter
|
Senior User
Joined: Jun 2007
Posts: 349
Likes: 0
if your flasher is going bonkers with the trailer hooked up, just get an electronic flasher. any parts store should have one. the electronic flasher controlls the flash cycle electricly instead of thermo-mechanically. It will just flash at a set rate regardless of the electrical load on the flasher. should only cost 10-15 bucks for the flasher unit. Had to do the same thing in my Crown-Vic ... worked like a charm.
Thread Starter
|
Senior User
Joined: Jun 2007
Posts: 349
Likes: 0
Yes you can splice, only if you have the old separate trailer lights like hasteranger said. However you do it, PLEASE DON'T USE SCOTCHLOCKS. Do it right, use butt connectors or solder that ish in there. Scotchlocks are gonna corrode on you in like a year if you live where they salt the roads. And you would be totally ruining that new harness that you just put in.
2) You need another resistor, like hasteranger said. The reason it blinks faster is because you have created a parallel circuit, decreasing total circuit resistance and increasing total circuit amperage. This is the same thing that happens when a blinker goes out, your blinkers blink faster because one of the filaments is burned out, and there's less total resistance.
2) You need another resistor, like hasteranger said. The reason it blinks faster is because you have created a parallel circuit, decreasing total circuit resistance and increasing total circuit amperage. This is the same thing that happens when a blinker goes out, your blinkers blink faster because one of the filaments is burned out, and there's less total resistance.
Trending Topics
Thread Starter
|
Senior User
Joined: Jun 2007
Posts: 349
Likes: 0
For your first question, it depends on how your trailer is wired. I am not familiar with the older 6 pin connectors and have never used one or wired a trailer with one, but I doubt they are that different than the newer style ones. If you have separate tail lights and turn signals then you would be fine to go ahead and wire them up wire for wire. If, like most modern trailers, you have a "stop/turn" as they call it, which is where you have only 2 lights on the rear and they are both running lights, and then a second filament is the brake like AND the turn signal, then you will need a controller. I guess its theoretically possible that your trailer would already have one integrated into the wiring, but I've never seen one that way. Usually the stop turn controller is behind the plug on the truck. The stop turn controller should have a resistor in it that would keep your turn signals from blinking too fast as well.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 6 Best Deals Available on New Fords & Lincolns Right Now
Brett Foote
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Verdad Gallardo
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Lead Driver
Joined: Mar 2010
Posts: 5,250
Likes: 11
From: West Virginia
i also really like the new fusion tape they have, you wrap it around something and it forms a solid layer of rubber as it fuses to itself. Its way easier to use than heat shrink, especially on a T splice. Heat shrink can be finnicky.
As for the question about whether are trucks are set up that way, now that I think about it, i believe that is correct, that the trucks are already set up with stop turn lights from the factory. I haven't really done any work on a truck with stock lights, though, since mine has a flatbed, so I couldn't say for sure.
Postmaster
Joined: Nov 2011
Posts: 2,553
Likes: 10
I'll just add, to fix the "fast flash" after splicing in the trailer wires and hooking up the traier, you need "heavy duty" turn signal and flasher units. They are avaialble at any autoparts store for $5-10. They will plug in to the harness under the dash. They look like a small round can. To find them, you can activate the turn signals or flashers and trace the sound they make.
The only drawback of the "heavy duty" units is they won't warn you if a bulb is out by a "slow flash". As long as you check your lights from time to time, no problem.
The only drawback of the "heavy duty" units is they won't warn you if a bulb is out by a "slow flash". As long as you check your lights from time to time, no problem.
Thread
Thread Starter
Forum
Replies
Last Post
magnoliarunner
2017 - 2022 Super Duty
5
Jan 17, 2018 11:16 AM
