Flat 4 Connectors

l008com

Senior Chief Petty Officer
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Jun 14, 2007
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730
The towing question is not actually Trailblazer specific, but still probably right on topic.

I have two small trailers I tow regularly. A 5x8 utility trailer and a smallish boat. My truck has a 6 pin plug, so I have a 6 pin to 4 pin adapter that I plug in and it works great.

But the trailers both have these cheap flat 4 cables that you can get everywhere. I keep having to replace them because they are all made so cheap. The wire insulation eventually breaks, shortly there after the copper fails. It's always the same deal. And back when I had an S10 which, rather than a heavy duty 6 pin socket, had just another flat 4 connector wire hanging down, the truck end would have the same problem!

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I've used different brands but they're all the same. Maybe these connectors are ok if you tow once or twice a year. But if you tow weekly, they're junk.

So my question is, does anyone know of a better system? I know the ultimate solution is that I Could upgrade both trailers to 6 pin heavy duty plugs. But I'd rather find some form of 'heavy duty' or just a quality 4 in plug, so I could maintain compatibility with other vehicles. Any suggestions?
 

brian4321

Petty Officer 1st Class
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Jan 19, 2014
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359
I have the same connecter on my trailer and have found if I keep the pins lubed with dielectric grease regularly they plug and unplug a lot easier and seem to last longer
 

Sprig

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May 2, 2016
Messages
574
A picture of one that failed or is going bad would be helpful. I've had those connectors on various boat trailers over the years and have never had a problem. Actually I replaced them one time. You might try putting some additional insulation over the first 6 to 12 inches of the wires to strengthen and secure them. There are several ways to do that. A simple and cheap way would be to tightly wrap electrical tape around them and then go over it with liquid tape or use some heat shrink tubing. Sounds like friction or stress is causing the insulation to fail.
 
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gm280

Supreme Mariner
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Jun 26, 2011
Messages
14,590
I have used the typical 4 connection flat connectors for years and never had any issues as well. But the key to them lasting long is to not allow them to dangle. I use a cover over the ends when not being trailered. But those covers came with the flat plug. And I tuck them up out of the way when not being used. I don't know if that helped but I haven't had to change any of them. JMHO
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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47,499
buy a higher quality flat-4 plug and wire set. use dielectric grease and caps to keep the terminals looking good. mine usually last about 8-10 years prior to being dragged on the ground because I forget to plug them in at the ram. I have a flat-5 on my trailer (disc brakes with a reverse solenoid) and I wired the truck with both a flat-4 and flat-5 connector.

if you drive where there is road salt, you really need to keep the connector capped. the available ground and 12 volts mixed with road salt will corrode the truck side harness in a short time. I replaced the trailer wiring on dad's truck for the 6th time in the trucks history this last spring (its a 1996). he never washes the truck and since its primarily a plow truck, his trailer connector is usually caked with winter road salt
 

lckstckn2smknbrls

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Sep 18, 2008
Messages
1,114
IIRC Hopkins sells replaceable ends. If it's just the wires going bad you can cut off an inch of wire and reinstall the end.
 

thumpar

Admiral
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Jun 21, 2007
Messages
6,138
I have had my trailer for over 3 years with no replacement and the owner before that used it but I don't know for how long ago or if the connector was ever replaced. I use a 7 way to 4 flat adapter. The trailer I had before had a replacement connector but only because I bought a whole kit that came with new wire for the lights I wanted.
 

l008com

Senior Chief Petty Officer
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Jun 14, 2007
Messages
730
This problem bit me again today. On my utility trailer, not my boat trailer. The flat4 connector on the trailer failed. Just as I was heading out to buy a weekends worth of work supplies at lowes. I guess I'm just going to solder up another cheap replacement for another year or two. Same old same old. I don't know how you guys are getting 8 years out of these connectors. Every one I've ever used has been such garbage. Right where the tires come out of the black plastic connector, they just start to split and fall apart. Maybe I should just upgrade my trailers to 7 way plugs. That will solve my problem, and give me an excuse for not letting people borrow the trailer any more :D

But seriously, in the meantime, if anyone has any suggestiosn for a specific flat 4 connector that isn't made poorly please post a link. Maybe something where all four conductors come out of the black plug grouped together, instead of all spread out. So the wires aren't taking all sorts of stress. That could help.
 
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ondarvr

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Apr 6, 2005
Messages
11,527
I buy the cheap ones and have them on many trailers, 17 years and it was changed once on the most used trailer, and that was from dragging on the ground. That trailer was used several times per week for years. But if you aren't getting that kind of life, switch to the same type on the truck now.
 

bigdee

Commander
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Jul 27, 2006
Messages
2,665
I have never had any issues. All 4 of my trailers have this type of plug, I keep them tucked out of the way. I don't plug them up often because lights are not required in NC during daytime unless trailer is large enough to hide tow vehicle's taillights..
 

KD4UPL

Senior Chief Petty Officer
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Feb 13, 2010
Messages
654
Cut the 4 pin off the wires. Install a 6 pin on the wires. Problem solved. No adapter needed.
 

am_dew

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Apr 3, 2005
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417
I have this one and it is much heavier duty than most....
 

charleso

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Nov 13, 2006
Messages
179
This problem bit me again today. On my utility trailer, not my boat trailer. The flat4 connector on the trailer failed. Just as I was heading out to buy a weekends worth of work supplies at lowes. I guess I'm just going to solder up another cheap replacement for another year or two. Same old same old. I don't know how you guys are getting 8 years out of these connectors. Every one I've ever used has been such garbage. Right where the tires come out of the black plastic connector, they just start to split and fall apart. Maybe I should just upgrade my trailers to 7 way plugs. That will solve my problem, and give me an excuse for not letting people borrow the trailer any more :D

But seriously, in the meantime, if anyone has any suggestiosn for a specific flat 4 connector that isn't made poorly please post a link. Maybe something where all four conductors come out of the black plug grouped together, instead of all spread out. So the wires aren't taking all sorts of stress. That could help.

Could you possibly be damaging the connector and or the wire when soldering? I always use good crimp connectors on my trailers(I absolutely HATE the pinch on, no strip connectors. I either use standard and seal them good with friction tape or use the heat shrink type connectors. Also, leave enough slack to allow for turns and avoid snatching the plugs when disconnecting.
 

roscoe

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Oct 30, 2002
Messages
21,665
You need to be holding the connectors in your hands, and not pushing and pulling and twisting on the wires when connecting them or disconnecting them.
Wrapping them with split loom and a few layers of tape will also support the wires so they aren't constantly getting bent back and forth.

The better quality Wesbar connector above will run you $9-13, and is quite stout, not like the $2.99 versions found at discount stores.
 

am_dew

Chief Petty Officer
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Apr 3, 2005
Messages
417
Another suggestion to avoid stress on the wires coming out of the plug is to slide 2-3 inches of heat shrink tubing up as close to to the plug as possible, forcing the wires together and then heat the shrink tubing up so it contarcts. This has to be done of course before you splice the loose wire end to the other wires. Or instead of heat shrink tubing, wrap some electrical tape around the four wires, again as close to the plug as possible.
 

am_dew

Chief Petty Officer
Joined
Apr 3, 2005
Messages
417
You need to be holding the connectors in your hands, and not pushing and pulling and twisting on the wires when connecting them or disconnecting them.
Wrapping them with split loom and a few layers of tape will also support the wires so they aren't constantly getting bent back and forth.

The better quality Wesbar connector above will run you $9-13, and is quite stout, not like the $2.99 versions found at discount stores.

Great advice above! :thumb:
 

mla2ofus

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Dec 30, 2008
Messages
571
If the wires are are in direct sunlight all the time it's not in use that will make the insulation brittle.
Mike
 

bigdee

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Jul 27, 2006
Messages
2,665
Just buy a 6/7 pin plug for less than $10 and you will no longer need a converter. I standardized all my trailers to use same plug,also replaced all the 1-7/8 hitches with 2' hitches. Makes life easier.
 

l008com

Senior Chief Petty Officer
Joined
Jun 14, 2007
Messages
730
So I bought an extension cable at the local auto parts store, chopped the end off and spliced it up. I don't even know what brand it was, but it seemed to be a much higher quality connector than the previous one, even though I got the previous one the same way. Hopefully I have better luck now. I don't really want to get a 6 pin plug on any of my trailers. Most vehicles to not have the plugs for them, and my next truck easily may not. Plus I loan the utility trailer out to people all the time. Easy way to bank favors.
 
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