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Jminz

Trailer brakes question

11 posts in this topic

The 220 SSI tandem trailer has a 4 pin harness. My old boat trailer has a 5 pin. To my understanding with a 4 pin the trailer brakes will not lock with the harness is disconnected from the vehicle. Is this correct? 

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4 pin usually means surge brakes.  surge brakes do not use any sort of electricity to stop, it uses force to pump an actuator which pumps fluid to your brakes.  5 pin should be surge brakes as well.  7 pin is usually for electric brakes.  The wiring harness is only controlling lights that's it, plugged in or not your brakes will work.  The 5 pin like I said is usually surge brakes, the fifth pin is usually for a lock out solenoid which while in reverse it locks out your actuator making it easier to back up. 

 If your new trailer has a four pin  chances of your being able to lock out the actuator with a solenoid and reverse easier is slim to none.  Another method to lock out the actuator is to put a c clamp down there

 

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I think the 5th pin (blue) is the Reverse solenoid lockout power supply. Without it, you will not be able to back the trailer without actuating the brakes, unless you engage a lockout pin.

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Does the trailer have drums or disc brakes?  I suspect it has drums if the connector is a flat four. You should be able to back up, as most trailer drum brakes  are "free backing".

If your trailer has disc brakes, then it will have a flat five connector. The extra 5th wire provides power to a lock-out solenoid in the coupler when your truck is shifted into reverse. Without the fifth wire, you cannot back up, as the trailer  brakes will be applied.

Hitch up and try backing up. You'll know quickly...

brick

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3 hours ago, Jminz said:

The 220 SSI tandem trailer has a 4 pin harness. My old boat trailer has a 5 pin. To my understanding with a 4 pin the trailer brakes will not lock with the harness is disconnected from the vehicle. Is this correct? 

Correct, with a four pin harness your brake system doesn't have a reverse solenoid. So you could leave it plugged in or not. With a 5 pin, it does have a reverse solenoid so it does have to be plugged in to go backwards (if it working properly).

 

.

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8 minutes ago, Toddler said:

Correct, with a four pin harness your brake system doesn't have a reverse solenoid. So you could leave it plugged in or not. With a 5 pin, it does have a reverse solenoid so it does have to be plugged in to go backwards (if it working properly).

 

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down hill or descent truck you can usually power through a lock out solenoid.  Like I said earlier poor mans lock out solenoid is a c clamp on the sliding portion of tongue.  Actually worked great on my last trailer, was tired of the solenoid failing and just went a clamp.

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21 minutes ago, soldier4402 said:

down hill or descent truck you can usually power through a lock out solenoid.  Like I said earlier poor mans lock out solenoid is a c clamp on the sliding portion of tongue.  Actually worked great on my last trailer, was tired of the solenoid failing and just went a clamp.

My UFP A60 coupler has a lock-out pin in case of solenoid failure. I have never had to use it, but good to have.

brick

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Just now, brick said:

My UFP A60 coupler has a lock-out pin in case of solenoid failure. I have never had to use it, but good to have.

brick

yeah good to have.  My older trailer didn't thus I went to a clamp.  I'm sure with right drill and a pin just about anybody could fashion one,  only thing with using a pin or clamp is make sure you take it out after backing up

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36 minutes ago, Jminz said:

Thanks for the info fellas

Post a picture of the coupler and brakes if you are still unsure. 

brick

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