5 pin to 4 pin

[ctb1010]

I just bought a new boat and trailer. The trailer has a 5 pin connector for the lights (it doesn't have brakes), my truck has a 4 pin connector. I can connect them and the blinkers work and the brake lights, but when I have my headlights on, the tail lights don't stay on. Is there an adapter I can buy that will just connect the two and give me all the functionality, or do I need to take it to a shop and have them do some wiring? I'm not super handy, but if it's fairly easy I could give it a try myself. Thanks for the tips! I've attached a pic of the trailer's cable:

 

[robopath]

You can get them online for less than $10.
http://amzn.com/B000CMHVGM

 

[smokeonthewater]

You have a bad ground or an incorrectly wired trailer.. The 5th wire is not used unless you have brakes or backup lights. You don't need an adapter.

 

[ctb1010]

Thanks! It looks like that requires me to cut and splice some wires though right?

 

[ctb1010]

Well shoot, I've got two different answers now, maybe I need to take it to a trailer repair shop to have it looked at.

 

[Starcraft5834]

You can get them online for less than $10.
http://amzn.com/B000CMHVGM

my thought also... probably just a short, loose wire....inspect and repair as needed

 

[Silvertip]

The pins on that connector look very corroded. Clean them with a brass bristle brush. Since the stop and turn signals work (they use the same filament in the trailer lights by the way) but the tail (running) lights don't it is obvious the problem lies in the running light circuit which happens to be the fourth socket from the bottom in your picture. The lower socket is ground and it is ok because other lights work. The next two are turn/stop and the fourth is running lights. So first verify that the truck side of the circuit is working. Check the fuse as there is usually one for trailer lights. Use a voltmeter or test light to test that circuit. If it shows 12 volts with the headlights on, the problem is on the trailer side. Since neither running light works, I suspect 1) the truck side is bad, 2) there is a broken brown wire on the trailer between the connector and the running lights, or 3) the running lights themselves are not properly grounded. You might just plug and unplug the connector several times to burnish those contacts a bit. It is also possible the brown wire is no longer connected to the pin inside the rubber plug. It is amazing how many people shoot themselves in the foot by pulling on the wires instead of the plug.

 

[smokeonthewater]

Well shoot, I've got two different answers now, maybe I need to take it to a trailer repair shop to have it looked at.

Trailer wiring is sooooo simple.... You have 3 positive wires (right turn, left turn, and tail) and you have one ground wire that handles the negative side of all three....

 

[UncleWillie]

For your Reference.
1. White --- Ground for Everything
2. Brown --- Tail Lights
3. Yellow --- Left Turn and Brake
4. Green --- Right Turn and Brake
5. Blue --- Brake Lockout (Reverse Lights)

If the Tail Lights are intermittent, the problem is in the Brown wiring.
The 5th Pin has nothing to do with the lights.
If your trail has a 5 pin connector it had Brakes! Where did they go! ??

In most states, if your Trailer, with the loaded/fueled Boat, weighs more than #3000; Brakes are required by law. Even less in some states.

 

[2 Eagles]

You have a problem is in the tail lights (Brown Wire, Second Pin from the bottom) or a ground (White Wire, Bottom Pin). UncleWillieis right on the pin and color code.Sivertip has the right color code, but the wrong pin order.
The pin order for your photo starting at the top and goinh down is:
5. Blue
4. Green
3.Yellow
2. Brown
1. White

 

[smokeonthewater]

BTW an easy way to remember which side the green and yellow go to is:
Green and right both have 5 letters...

 

[UncleWillie]

BTW an easy way to remember which side the green and yellow go to is:
Green and right both have 5 letters...

Another way I use is....

yeLLow = Left

gReen = Right

 

[thumpar]

If you know your vehicle wiring is good I would just buy one of the kits to redo the lights and wiring. I did it on my last trailer. They are less than $50 and include everything you need. To run the new wire I just taped it to the old wires and pulled it through each side.

 

[Brian 26]

Trailer wiring is sooooo simple.... You have 3 positive wires (right turn, left turn, and tail) and you have one ground wire that handles the negative side of all three....

+1 it only gets complicated when you try to chase broken wires that are hiding inside the frame of the trailer

Step 1 gut old wires
Step 2 put in new wires
Step 3 stand back and drink beer knowing you are one of few people on the road with trailer lights that work.

 

[smokeonthewater]

And while you're at it install all new led lights and use waterproof heat shrink connectors.... Then you have very little chance of having to work on those trailer lights again in the next 15 years.

 

[Silvertip]

My bad!

 

[FISHVA88]

Just to be sure, I'd take a look at the bulbs back there. I had a problem this year where my running lights were working fine, but turn signals wouldn't work. Everything tested fine. Just when I had about given up, I checked the bulbs. The filament for the running light was in tact on both sides, but the turn signal filament was shot on both sides. It turned out to be a $5, 5 minute fix. Glad I checked.