Wiring harness

[BayouBob]

I upgraded my boat last fall and the new trailer has brakes on it. The new wiring harness on the trailer is a 5 prong and my SS has the adapter for a 4 prong on it. Does anyone know if you can buy this or will I have to make it?

[RayVoy]

Most of the trucks have the 7 pin connector, but the SS may use the 4 pin IDK. Could it be a 7 to 4 pin converter just plugged into the 7 pin plug. If so, can you find a 7 pin to 5 pin converter?

[toolmantr]

For my SS, I needed a 7 blade RV receptacle. I bought an adapter from Hopkins Towing; the Multi-Tow. It is a 4-wire flat and 7-blade round. If you can get a 7-5 adapter, you could combine it with the Hopkins. Or, you can get a generic 5 pin and cut the 4 off the factory harness and rewire it to fit your application. The Hopkins was plug-and-play, that's why I went for it.

[the roadie]

Once you get the right outside connector on the harness (the SS IIRC has all seven wires in the rear, but you have to put your own connector on the GM harness), you'll still need a trailer brake controller wired into a 4-wire harness (just wires curled up and electrical taped together) up near the driver's left foot.

[toolmantr]

I run a Tekonsha Prodigy brake control. It is an excellent unit, easy to install and easy to adjust. Since my camper has a battery, I chose to attach the power line to the fuse terminal under the hood. This powers the plug for charging while towing.

[Selvig]

The fifth wire is used when the trailer has disk surge brakes. Unlike drum brakes on a trailer it is impossible to back up the trailer without disabling the brakes, something will brake or you will drage the trailer tires and grind down the tires. A fith wire is needed to open up a solenoid that causes the surge brakes not to work when backing up the trailer. The fifth wire is hooked up to the back up lights to activate the surge brake solenoid.

There is available through various vendors a 7 pin round to 5 flat adapter. Also available are two 7 pin round to 5 flat pig tails that stretch to either 3 or 5-6 feet.


Chris Selvig

[mrtillie]

The fifth wire is used when the trailer has disk surge brakes. Unlike drum brakes on a trailer it is impossible to back up the trailer without disabling the brakes, something will brake or you will drage the trailer tires and grind down the tires. A fith wire is needed to open up a solenoid that causes the surge brakes not to work when backing up the trailer. The fifth wire is hooked up to the back up lights to activate the surge brake solenoid.

There is available through various vendors a 7 pin round to 5 flat adapter. Also available are two 7 pin round to 5 flat pig tails that stretch to either 3 or 5-6 feet.


Chris Selvig

Thats right Chris... I just bought a new boat a trailer and it has a 5 pin and surge brakes. My dealer set me up with the 7 to 5 pin i needed and i was away.
If your in a bind and need to backup and dont have a 5 pin you can always run a wire from your park lights and hook it to the last wire on the 5 pin which is blue. and that will unlock the surge brake system.:tiphat

[lynch55]

:thxThat is a good idea! But why would manufacturers design a system where you can't back up your trailer? Oh thats right, they probably get a kickback on the adapters!

[Selvig]

If you have no access to the fifth wire and need to back up with Disc brakes, there is a hole in the movable hitch to insert the trailer locking pin that prevents the surge from working. This allows backing up. Do not leave the pin in this hole while traveling down the road as there will be no brakes when needed and the hitch will also not be locked to the ball.


Chris