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ryanowen

5th pin on trailer wiring

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ryanowen

I've seen the round 7 pin connectors and the flat 4 pin connectors, but my new-to-me trailer has a 5 pin flat connector. I'm guessing the 5th pin has something to do with the brakes, but I don't really understand because they are just surge brakes. My last trailer had surge brakes and a 4 pin. Anyone know?

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robtr8

It's tied to the reverse light. Activates a lockout for the brake pressure so that you can back up.

http://www.etrailer.com/faq-wiring.aspx

In the diagram they show a purple wire but mine is blue.

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Vettesetter

It activates the reverse solenoid allowing you to reverse up hill.

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W.S. Walcott

The 5th pin locks out your surge brake while backing up (back up light signal engages a solenoid). They make 7 to 5 pin adapters as well. If you're trying to back your trailer up hill the brakes will lock up without it. There should also be a "delete" hole that you can stick a pin through in case you don't have the 5th wire or the solenoid stops working.

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joshuadale07

5 pin will have your running lights (brown usually) left and right turn/brake (green and yellow wire) and a positive and negative for brakes usually. It may not have anything connected to the 2 extra pins. 5 pins are older style and if the trailer is old that may be why it's on there if it's factory wiring. If it was added it's possible the tow vehicle before only had the 5 pin receiver on his truck

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mrnate450r

The 5th pin is for the reverse brake release. I only needed it on my last boat when I backed it into my driveway.

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Soon2BV

My 2008 Boatmate came with the flat 5 connector.

The e-trailer site referenced above is an awesome website - lots of great information and help pages.

i have it bookmarked.

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ryanowen

Thanks everyone. That makes sense. According to the PO, the 5 wire connector came with it. The vehicle I'll be towing with normally only has a 4 pin, so it sounds like I'll need an adapter and need to use the delete hole if needed. I wonder why my last surge trailer didn't have the 5th wire... maybe it had a spot for the pin and I just never noticed? I guess I never really backed up any substantial hills.

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G-Mack

Was your old trailer drum brakes? You can overcome drum brakes in reverse based on the geometry of drum brakes. You can't overcome the disc brakes in reverse they stop as well in reverse as in forward.

If you don't run the 5 the wire for the solenoid lock out you will need to use the ping to manually lockout the surge brake when backing up. Works just as well just more effort.

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formulaben

Thanks everyone. That makes sense. According to the PO, the 5 wire connector came with it. The vehicle I'll be towing with normally only has a 4 pin, so it sounds like I'll need an adapter and need to use the delete hole if needed. I wonder why my last surge trailer didn't have the 5th wire... maybe it had a spot for the pin and I just never noticed? I guess I never really backed up any substantial hills.

This is what I installed...was quick and painless.

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CumminsBu

I changed mine to a 7 rounded, if your tow vehicle has it I would go that route.

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ryanowen

Was your old trailer drum brakes? You can overcome drum brakes in reverse based on the geometry of drum brakes. You can't overcome the disc brakes in reverse they stop as well in reverse as in forward.

If you don't run the 5 the wire for the solenoid lock out you will need to use the ping to manually lockout the surge brake when backing up. Works just as well just more effort.

Spot on. That's exactly what it had. I guess that's why it wasn't an issue before.

This is what I installed...was quick and painless.

I also used the 4pin -> 5pin adapter similar to formulaben. The one I installed was similar, but shorter - http://www.etrailer.com/Wiring/Hopkins/47515.html

Those both look like they could work. Thanks for the links.

I changed mine to a 7 rounded, if your tow vehicle has it I would go that route.

My tow vehicle only has a 4, so I think I'm going to be stuck working with the 5 pin.

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BlastRlxi

If you need to use the the reverse lockout to back into a driveway or something, you can take the 5th pin (brake lockout) and tee it into one of the other pins from the tow vehicle. The pin used to power the trailer lights when the tow vehicle's headlights are on is a good one. You just have to reconfigure it this way while you're backing up.

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mrnate450r

If you need to use the the reverse lockout to back into a driveway or something, you can take the 5th pin (brake lockout) and tee it into one of the other pins from the tow vehicle. The pin used to power the trailer lights when the tow vehicle's headlights are on is a good one. You just have to reconfigure it this way while you're backing up.

I just flipped my plug over and turned the headlights on. That way the 5th plug is plugged in.

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ahopkinsVTX

The Hopkins adaptor works well, of course right? ;) I used it for half of the season last year then I got tired of looking at two plugs so I just bought a flat 5 vehicle end plug and wired it in using the existing wiring for the 4 pin and the extra wire for the Hopkins adaptor. Not that is was expensive to do both but looking back I would just go straight to the flat five and tie I to the reverse light wiring on one of your tail lights.

EDIT: http://www.amazon.com/gp/product/B001GKDE06/ref=oh_details_o03_s00_i00?ie=UTF8&psc=1 The blue wire on this would go to your reverse light wiring in your tail light, you will probably have to add length to it. If you wanted to go that route.

Edited by ahopkinsTXi

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ryanowen

The Hopkins adaptor works well, of course right? ;) I used it for half of the season last year then I got tired of looking at two plugs so I just bought a flat 5 vehicle end plug and wired it in using the existing wiring for the 4 pin and the extra wire for the Hopkins adaptor. Not that is was expensive to do both but looking back I would just go straight to the flat five and tie I to the reverse light wiring on one of your tail lights.

EDIT: http://www.amazon.com/gp/product/B001GKDE06/ref=oh_details_o03_s00_i00?ie=UTF8&psc=1 The blue wire on this would go to your reverse light wiring in your tail light, you will probably have to add length to it. If you wanted to go that route.

Since my tow vehicle doesn't have a hitch or wiring at all yet (it's not even built!), I'm pretty much starting from scratch. The hitch kit has a bracket for a 4 pin connector, but I might be able to modify it for a 5 and then just not use an adapter at all when I'm towing my boat.

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ahopkinsVTX

Since my tow vehicle doesn't have a hitch or wiring at all yet (it's not even built!), I'm pretty much starting from scratch. The hitch kit has a bracket for a 4 pin connector, but I might be able to modify it for a 5 and then just not use an adapter at all when I'm towing my boat.

If that is the case I would have them put in the 7 pin with the tow package, which is probably already what they would do. Then you can use a 7 pin to 5 pin adapter. What are you getting?

Lots of different adapters for 7 to 5, but I have had good luck with this one on other vehicles. http://www.etrailer.com/Wiring/Optronics/A57WB.html

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ryanowen

If that is the case I would have them put in the 7 pin with the tow package, which is probably already what they would do. Then you can use a 7 pin to 5 pin adapter. What are you getting?

Lots of different adapters for 7 to 5, but I have had good luck with this one on other vehicles. http://www.etrailer.com/Wiring/Optronics/A57WB.html

I'm installing it myself. It's going on a Jeep Wrangler Unlimited. It's already kind of pushing the limit as a tow vehicle for this setup, so I don't think I'll ever use a 7 pin. The hitch kit came with a 4 pin harness, so maybe I can modify the harness to be used as a 5 pin. This is the kit.

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Bozboat

I'm installing it myself. It's going on a Jeep Wrangler Unlimited. It's already kind of pushing the limit as a tow vehicle for this setup, so I don't think I'll ever use a 7 pin. The hitch kit came with a 4 pin harness, so maybe I can modify the harness to be used as a 5 pin. This is the kit.

I seem to remember someone saying that you can reverse the five pin 180 degrees or move it over or something when you plug it into the four pin when you are ready to back up.

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Deven

I'm installing it myself. It's going on a Jeep Wrangler Unlimited. It's already kind of pushing the limit as a tow vehicle for this setup, so I don't think I'll ever use a 7 pin. The hitch kit came with a 4 pin harness, so maybe I can modify the harness to be used as a 5 pin. This is the kit.

You would be much better off getting a class III receiver. You are going to be over the limits of that class II with a loaded boat and trailer.

Class II Trailer Hitch Receivers:

  • Designed for light-duty towing
  • Are rated up to 3,500 lbs GTW and 350 lbs TW

Nevermind. Towing with a Wrangler.. I hope you aren't going very far.

Edited by Deven

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ahopkinsVTX

I'm installing it myself. It's going on a Jeep Wrangler Unlimited. It's already kind of pushing the limit as a tow vehicle for this setup, so I don't think I'll ever use a 7 pin. The hitch kit came with a 4 pin harness, so maybe I can modify the harness to be used as a 5 pin. This is the kit.

I see. It is hard to tell from those pictures but the 4 pin that comes with it should have standard wiring (4 wires). If it were me, I would skip the adapter and order the 5 flat pin, cut the 4 pin off of that wiring harness, reconnect same colored wires through butt connectors, then run the blue wire from the 5 pin to the tail light reverse power wire (probably white). Wasn't hard at all when I did mine.

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ryanowen

Nevermind. Towing with a Wrangler.. I hope you aren't going very far.

Exactly. The vehicle is only rated for 3500 anyway, so a class 3 wouldn't help. I'm not towing far at all. Twice a year, maybe 10 miles from storage to the lake area and then through-out the summer a bunch of quarter mile trips back and forth to the lake.

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ryanowen

I see. It is hard to tell from those pictures but the 4 pin that comes with it should have standard wiring (4 wires). If it were me, I would skip the adapter and order the 5 flat pin, cut the 4 pin off of that wiring harness, reconnect same colored wires through butt connectors, then run the blue wire from the 5 pin to the tail light reverse power wire (probably white). Wasn't hard at all when I did mine.

I think that's exactly what I'll try. That'll make for a slick setup that I don't need an adapter for and don't need to get in and out of the vehicle to back up.

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ahopkinsVTX

I think that's exactly what I'll try. That'll make for a slick setup that I don't need an adapter for and don't need to get in and out of the vehicle to back up.

Yep! I would just buy a small box of splice connectors like the one shown in the Hopkins adaptor to tie into the power cord to reverse light. No cutting or anything then.

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