Posted 2006-07-06 10:48 AM (#44143) Subject: Trailer wiring, 7 to 6 pin adapers, etc.
Expert
Posts: 2689
I know, in the past I've said to just chop off any 6 pin connectors from old trailers and re-wire to current 7 pin truck standards, but - there's always a big BUTT !!!
I moved an old trailer for someone recently, it had a 6 pin connector, my truck has 7 pin, I have a 7 to 6 pin adapter, so thought it would be an easy hook up and go. Nothing worked, no lights, brakes, turn signals. Since it was a short rural hop I chanced it (bad me, I know).
Anyway, we're still trying to get this old trailer figured out and the trailer wiring document on this site's home page has a note saying that RVs often use the center pin for electric brakes whereas horse trailers often use that pin for +12V.
The eureka moment was when I noticed that the adapter plug has "E brake center pin" molded into it - come to think of it I probably bought that adapter at an RV store. There are PROBABLY 7 to 6 pin adapters that have "E brake pin S" molded into them. Point is the thing comes apart and you can switch the wires around, it isn't a one piece molded_together_forever thing.
Posted 2006-07-06 11:54 AM (#44148 - in reply to #44143) Subject: RE: Trailer wiring, 7 to 6 pin adapers, etc.
Extreme Veteran
Posts: 524 Location: Lone Oak, Tx
Thanks for the heads up Reg. My truck has the 7 pin wired to it and the trailer has the 6 pin. I'm wondering if I might have any problems if I have to tow someone else's trailer. I had to replace the female socket in the truck and my 6 to 7 adapter this past weekend due to me being a dumbdumb and not taking out the umbilical before pulling away from the trailer. While replacing the the female connection I noticed that the wires were not hooked up to the colors listed on the connector. Glad I noticed that cause if I wouldn't have put everything back the way it was I'd of been puling my hair out trying to figure that out.
Posted 2006-07-07 7:38 AM (#44188 - in reply to #44143) Subject: RE: Trailer wiring, 7 to 6 pin adapers, etc.
Member
Posts: 26 Location: Ontario, Canada
I've made several adaptors that are all homemade using connectors. When dealing with older trailers, I've found that there are basically two or three things to remember. 1. A test light is your best friend. 2. Don't assume anything about what 'the other guy' did. 3. Bad ground connections cost a lot of people a lot of hair.
I remember being asked by friends several years ago to move a trailer for them after their pickup had died, it had surge brakes, so only had a 4 pin flat connector. When I went to join them I had to scratch my head, at some point the connectors had been changed, and the wrong ends used on truck/trailer. This meant the truck end had the 3 live wires for feeding the lights exposed whenever the trailer was disconnected!! Fortunately I had a spare connector with me in the truck (I often do) and was able to wire up something to work. A roll of electrical tape is a necessity to have in the glove box too, it's my version of duct tape.
Trailer wiring, 7 to 6 pin adapers, etc.
