Re-doing Trailer/Toad wiring

[Nuke-E]

I've been disappointed by the off-the-shelf 7-wire RV plugs I've gotten at local parts stores, so I started looking for something better. Even though it has only been on there a year or so, the screws are pretty rusty, and 2 of the rather thin mounting ears have broken off-leaving me with a dangling plug. To be fair, the back side of the plug is exposed to a fair amount of spray, and the wire loom was packed full of dirt, but it was getting almost impossible to keep the lights on the car as bright as they should be.

 

Tonight I finally got underneath the back end to follow the wiring, cut a bunch of zip ties, and get it out of there. It's over eight feet long, and most of that was coiled up:

Here's the replacement:

 

It's a Pollack 11-893, less than $10 each. It looks a lot more sturdy, and instead of screw terminals it's designed to plug in to a harness with a Metri-Pack style connector (same terminal and weather seals as the rest of the Volvo wiring, I think I paid about $20 for a 4' harness, #11-998). I also like that they give you the pin-out in plain English on the cover:

 

The circuit breakers where everything meets up with the truck harness were looking a little worse for wear, so replacements are on the way.

 

[dascom]

I know several have used the standard DOT connector by changing their trailer plug for that very reason. Most of the RV connectors I have seen are cheap and unreliable. There is something to be said about compatibility so one might latch on to a different trailer to help someone out. That concern can easily be handled by an adapter. Thanks for the information Dave, those round pin connectors look like the cats meow.

[Mark and Dale Bruss]

 

 

Thanks for the information Dave, those round pin connectors look like the cats meow.

I think you missed the point. The trailer receptacle end is still 7 blades.

 

It is the back end where the wires attach that can use an industry standard plug instead of screw terminals.

[Nuke-E]

Mark is right--it's still a standard RV plug as far as connecting a trailer is concerned:

 

[dascom]

Just saying, move those 7 trailer plug wires to a reliable style plug as many of us have done. The industry standard is junk.

[jkennell]

Amen. Or even better...use a EURO standard plug IF you can get your hands on one.

 

Those are a big improvement over the cheap ones, though. Do yourself a favor and pack the Metripack area with silicon grease during installation. Keeping these clean and shiny is key to longevity. (Actually, a screw terminal is very reliable-- they rarely loose contact there. Its usually the crimp to the wire on the terminal.)

[Mark and Dale Bruss]

Actually there is some benefit of blade over round contacts. As the blades slide into the receptacle contacts, there is a scrubbing action as the contacts have a spring force against the blades. Every time the plug blades are inserted, there is a cleaning action.

 

There is limitations of what spring action can be invoked by a sleeve around a round plug.

 

I switched over from using a 4 round pin plug/receptacle for my trailer camera because the contacts would not stay clean. The spring action was in the pins, a slit in the pin was supposed to scrub the pin against the sleeve. The pin looses its spring action rather quickly.

 

I switched to using a 7-blade plug/receptacle for the trailer camera and haven't had a problem since. Sometimes overkill is good.

 

I replace the trailer plugs and receptacles every couple of years mainly due to galvanic corrosion of the +12v and ground contacts.

 

I like the unit Nuke-E is using as it would make a replacement of the receptacle very easy, just pop out the old and pop in the new without screwing around with 7 wire terminals.

[Jack Mayer]

Actually there is some benefit of blade over round contacts.

 

There is limitations of what spring action can be invoked by a sleeve around a round plug.

 

I switched over from using a 4 round pin plug/receptacle for my trailer camera because the contacts would not stay clean. The spring action was in the pins, a slit in the pin was supposed to scrub the pin against the sleeve. The pin looses its spring action rather quickly.

 

I switched to using a 7-blade plug/receptacle for the trailer camera and haven't had a problem since. Sometimes overkill is good.

 

I did the same thing, years ago, for the same reasons. Never an issue since.