Trailer lights

[danielcasey01]

thank you!!

 

[mrmeaniemeateaterman]

The first 2 question we should always ask with any of these trailer wiring questions is:
Do you have a light circuit tester?
Do you know how to work it?

I'm guessing in all cases the answer is no, otherwise they wouldn't be here asking. I keep one of these in my glove box. I bet I use it 5X a year to diagnose various issues with all the trailers I have. Without one you are just guessing at everything. Plenty of videos on youtube to explain how it works such as this.

 

[danielcasey01]

thank you and I will pick one up.

 

[Adrian @ JB Solutions]

thank you and I will pick one up.

I would strongly recommend a DMM over a light tester.

 

[mrmeaniemeateaterman]

DMM is Digital Multi Meter or at least I assume that's what you mean.
I'm guessing if people don't know how to use a light tester then they have no clue what a DMM is or how to use that either.
They have their place but a light tester is super simple. K.I.S.S. in full effect.

 

[Ronnie]

Thanks! So i put a nickel in there to stop it from moving backwards?

Only use a nickel if you don’t have a D key and only tape it or the D key in to keep it from falling out while you position the trailer (sometimes I have to shift from reverse to forward when backing my boat up a slight incline and into a ramp. There is also a magnetic version available online for about $15). These mechanical blocks should be removed before towing the trailer / boat down the road to your destination. If it’s not the trailer brakes will not engage as they should / when they should.

I’ve had trailer lighting problems before, several times. I’m all instances it was a bad ground. Sometimes just cleaning the connecting pins solved the problem other times I had to remove the ground wire and Scuff up the area it’s screwed to (remove rust/dirt) before reconnecting the ground.

On a related note once you get the trailer lights to come on you can simply plug the 5 pin into the 4 pin leaving the last pin on the 5 floating free. This will allow the trailer lights to work but not the the reverse solenoid lockout to which can be addressed by using the D key or nickel when you need to (usually when you want to push the trailer back with the tow vehicle, especially up a hill / driveway). Trust me you will know if your trailer brakes are engaged if you try to back up a hill/driveway, my trailer wheels lock up.

 

[212s]

I'm guessing a bad ground wire somewhere if nothing works. Check the 5-4 pin adapter - if there is a second white wire, you need it grounded to the vehicle for it to work.

As for the blue reverse lockout wire, I don't use it since I unplug my lights when dunking the trailer (I have a 7-pin round socket on my vehicle). So I use a reverse lockout key from Amazon that is magnetic:

Amazon.com

Just make sure you remove it before you take the boat down the road! The boat trailer should have a lockout key with it, but they're designed to fall out when you pull forward so the brakes can work again and they're a pain to work with. The magnetic one doesn't fall out and is much easier to use. I have a process where I pull the lighting cord, insert the lockout key. When I'm getting ready to leave, I pull out the key and connect the lighting cord again. I keep the lockout key in the back of the truck beside the dock lines so it's always handy.

 

[danielcasey01]

Thanks. The adapter has a blue wire coming out of it which I'm guessing I need to connect to the ground?

 

[Ronnie]

Thanks. The adapter has a blue wire coming out of it which I'm guessing I need to connect to the ground?

The blue wire is the reverse lead, that’s supposed to be connected to the reverse solenoid in the surge break usually via the fifth pin. If it’s connected properly and the solenoid is working the brakes on the trailer will be disengaged electronically when the tow vehicle is in reverse, it also means that you don’t need to use the d key or a nickel when the electronics are working.