electric brakes

[hoseman28]

Hello I recently bought a trailer with electric brakes and it has a four post light hook up .My question is can the brakes work with that or do you need like a 6 or seven prong to make them work?My truck has the brake box hooked up and I have both 4 and the big round hook ups.I dont really even know if the brakes are working ,what kind of safety check should I do ? Thanks

[wallace]

You will need a 7m prong.
I would go with the 7 over the 6 because all newer trucks are 7 prong.
If you google trailer wiring diagrams you will find what you need.
Also make sure you are in compliant with your state laws.
I know in Pa we need brakes on every wheel if the trailer is licenced over 3,000lbs, we also need a breakaway.

[Bird]

Originally Posted by hoseman28

Hello I recently bought a trailer with electric brakes and it has a four post light hook up .My question is can the brakes work with that or do you need like a 6 or seven prong to make them work?My truck has the brake box hooked up and I have both 4 and the big round hook ups.I dont really even know if the brakes are working ,what kind of safety check should I do ? Thanks

Welcome to Tractorbynet. I don't think I understand about the "four post light hook up". Are you saying the trailer currently has a 4 prong plug on the wiring? If so, I would think the trailer doesn't have electric brakes, or else they're disconnected. Of course, I agree with Wallace that you need a 7 prong plug.

[Heywood Jannockitov]

I replaced all my existing trailer wiring connectors that weren't already 7 pin with the "RV" Bargmann style connectors and plugs. This is pretty much the standard now around here anyway. I used to mess with adapters, but I have found them to be unreliable.

[George2615]

Welcome to TBN. Most GM trucks with tow pkg come with the 7 pin bargmann style plug. A 4 pin plug is only good for left turn, right turn, parking, and ground. You need the 7 pin for trailer brakes.
Safety checks would include:
1) Jacking up the axles and removing and inspecting the brake shoes / drums to see if they need replacing.
2) Wiring can be checked for continuity from the brake coils to the plug on the trailer. Magnet coils can be checked with an ohm meter and should show resistance.
3) Once you know which wire in the trailer plug feeds the brakes they can be tested with a 12V battery, a good ground, and an assistant to see if they stop the wheel from turning when power is applied to the coils.
Its fairly simple to do if your mechanically inclined. If not get a friend who is to help.

[hoseman28]

Thank you very much for your help.I will do the steps to correct the problems.I have the 7 prong on my truck 97 Dodge so it shouldn't be hard to fix the brakes so they are correct.

[Diamondpilot]

Most everyone is using the 7 pin. I see them on GM, Ford, Dodge, Nissan, Toyota, and Jeep. I sell boat trailers and that is what I set customers up with if they have no factory wiring.

Chris

[RobS]

Make sure you have a brake controller in your truck. Is that the "brake box" you mentioned? Having the 7-pin connector out back is a plus but you may just have an empty connector under the dash for a controller. No controller = no brakes!