# Pickup truck to trailer connection **URL:** \ **Category:** Factual Questions\ **Created:** [July 21, 2008, 9:27pm UTC](https://boards.straightdope.com/t/pickup-truck-to-trailer-connection/457305 "2008-07-21T21:27:23Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![SlickRoenick](https://avatars.discourse-cdn.com/v4/letter/s/e68b1a/32.png) [@SlickRoenick](https://boards.straightdope.com/u/SlickRoenick)\ **Post date:** [July 21, 2008, 9:27pm UTC](https://boards.straightdope.com/t/pickup-truck-to-trailer-connection/457305/1 "2008-07-21T21:27:23Z")
I have a 2004 Nissan Titan and next to the hitch receiver i have this [modern-looking piece of connection](http://smg.photobucket.com/albums/v284/SlickUSA/?action=view¤t=DSCN5518.jpg). I also acquired a trailer, no idea of make/model/year but it has this [old-looking ugly connection.](http://smg.photobucket.com/albums/v284/SlickUSA/?action=view¤t=DSCN5517.jpg) I also have [this harness](http://smg.photobucket.com/albums/v284/SlickUSA/?action=view¤t=DSCN5519.jpg) that came with the Titan but i think it’s supposed to be used for trailers that have electric brake _systems_, not regular electric brake _lights_–so correct me if i’m wrong but i think this is useless in my case. Is there such an adapter to use for connecting the brake lights? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [July 21, 2008, 9:28pm UTC](https://boards.straightdope.com/t/pickup-truck-to-trailer-connection/457305/2 "2008-07-21T21:28:49Z")
Yup. Go to your local Checker or Auto Zone. ---
**Author:** ![Mr.Goob](https://avatars.discourse-cdn.com/v4/letter/m/c77e96/32.png) [@Mr.Goob](https://boards.straightdope.com/u/Mr.Goob)\ **Post date:** [July 21, 2008, 9:56pm UTC](https://boards.straightdope.com/t/pickup-truck-to-trailer-connection/457305/3 "2008-07-21T21:56:25Z")
**Beuwolff** is correct. The four pin plug on the trailer is just for lights on a lightweight trailer that doesn’t need electric brakes. Go to any auto parts place and ask for a pig-tail for trailer wires. Four pins on one side, the 8 pin round connector on the other. ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [July 21, 2008, 10:08pm UTC](https://boards.straightdope.com/t/pickup-truck-to-trailer-connection/457305/4 "2008-07-21T22:08:01Z")
[[QUOTE=etrailer.com](http://QUOTE=etrailer.com)] If your truck has the connector on the left, and your trailer has the connector on the right, you will want this adapter. [/QUOTE] [http://www.etrailer.com/pc-A~37358.htm](http://www.etrailer.com/pc-A~37358.htm) Both my buddy and I have bought from these guys before, I’ve been pleased with their prices and service. Looks like you’re looking at $10 to $20, depending on how fancy you wanna get. **Mr. Goob** , I don’t believe they make an 8 pin trailer connection: [http://www.etrailer.com/c-a.htm](http://www.etrailer.com/c-a.htm) ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [July 21, 2008, 11:52pm UTC](https://boards.straightdope.com/t/pickup-truck-to-trailer-connection/457305/5 "2008-07-21T23:52:21Z")
That little gazakas in **Santo Rugger’s** first link is exactly what you want to plug in a basic trailer without electric brakes. Before you buy one - look behind your truck’s bumper. There just might be a 4-pin trailer plug back there behind the 7-blade RV connector. (My Dodge has both of these things factory-installed. No idea about Nissan. For the OP - as you guessed, that “elec brake jumper” harness is indeed to connect an electric brake controller. Somewhere under your dash will be a mating socket for that white plug. The other ends of the wires are connected to a brake controller as listed on that tag. You won’t be getting involved with this unless you’ve got an RV or a really big and heavy trailer. ---
**Author:** ![SlickRoenick](https://avatars.discourse-cdn.com/v4/letter/s/e68b1a/32.png) [@SlickRoenick](https://boards.straightdope.com/u/SlickRoenick)\ **Post date:** [July 22, 2008, 1:27am UTC](https://boards.straightdope.com/t/pickup-truck-to-trailer-connection/457305/6 "2008-07-22T01:27:17Z")
Beautiful advice. I went to Advance Auto Parts and got one for $8.50. I’m new to the whole trailer thing. I found out that i’m really good at backing it up without jack-knifing the bloody thing. Thanks all. ---
**Author:** ![Mr.Goob](https://avatars.discourse-cdn.com/v4/letter/m/c77e96/32.png) [@Mr.Goob](https://boards.straightdope.com/u/Mr.Goob)\ **Post date:** [July 22, 2008, 11:16pm UTC](https://boards.straightdope.com/t/pickup-truck-to-trailer-connection/457305/7 "2008-07-22T23:16:00Z")
[QUOTE=Santo Rugger] **Mr. Goob** , I don’t believe they make an 8 pin trailer connection: [http://www.etrailer.com/c-a.htm](http://www.etrailer.com/c-a.htm) [/QUOTE] 8 or 7 I just counted the pins in the picture. You got the idea. 🙂 ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [July 23, 2008, 4:50am UTC](https://boards.straightdope.com/t/pickup-truck-to-trailer-connection/457305/8 "2008-07-23T04:50:50Z")
[QUOTE=Mr. Goob] 8 or 7 I just counted the pins in the picture. You got the idea. 🙂 [/QUOTE] I think it’s because the middle two tabs only count as one pin because they support the ground, but I could be wrong. I just didn’t want Slick going to the parts place and asking for an 8 pin… they’d probably try to sell him blinker fluid and muffler bearings after that. :smack: ---
**Author:** ![vetbridge](https://avatars.discourse-cdn.com/v4/letter/v/b5e925/32.png) [@vetbridge](https://boards.straightdope.com/u/vetbridge)\ **Post date:** [July 23, 2008, 3:54pm UTC](https://boards.straightdope.com/t/pickup-truck-to-trailer-connection/457305/9 "2008-07-23T15:54:34Z")
[QUOTE=SlickRoenick] I found out that i’m really good at backing it up without jack-knifing the bloody thing. [/QUOTE] I’ve gotten good with practice, but if you hang around a public boat launch in the summer, you can get a good laugh. I’ve seen a few boats launched with the drain plug(s) not in place. I also saw someone moving their boat via a ball mounted on the _front_ of their vehicle. A guy standing by me muttered, “pussies” when we saw that.