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What Trailer Wiring Kit for 620 Pickup ??


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IMO anything that is more than a universal 4 pin setup would be too much for the Datsun. No double axle. No boxed trailer. No brake assist. Reason I say that is because these trucks are not that heavy. Tho I heard of ppl hauling other datsuns. There is also a thread with ppl doing real truck work. Personally I would keep it at loading only the bed but thats just me...

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I checked into this some time ago and it seems there should be a limit to what you can haul based on the hauling vehicle's weight or GVW. It seems that this is ignored and it's up to the owner to use common sense.... right. 



Like if your truck weighs 2,700 you can haul half that weight or maybe 3/4 on a trailer. I could not find a definitive answer.


I had 4x4x6' of fir on my 620 truck's flat bed that's about 3/4 of a cord. Using on line calculators the lightest wood was about 2,500 pounds for 3/4 cord, fir would have been even heavier perhaps over 3,000 lbs!!!.... glad I didn't know that then. I had F-150 leaf springs and 33  X 12.5 tires. It rode VERY well but brakes were almost non existent. Pulling a trailer with even half that? forget it.



But I digress....


What ever you do make very solid and soldered connections and seal with heat shrink tubing. I was the owner of a 521 that had innumerable rear tail light problems. Eventually I unwrapped the wire harness and found a bunch of blue copper sulfate and corroded copper wires in a bundle around a hack job trailer wiring connection that had been cut off. The environment under a vehicle is horrid and unforgiving. Rocks and flying dirt, water, salt. If allowed, it will get in.

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Early Datsuns have the turn signal lights separate from the brake lights, so 5 different wires, but to use a trailer with a light on each side, you will need a converter which combines the brake lights/turn signals, so a 4 wire connector and converter are all that is needed unless you have trailer brakes.

As for how much one should haul on or behind a Datsun, it really depends on who is driving, I have hauled insane amounts of weight with my Datsun work truck, and I have towed other trucks, which include Datsun/Nissan 720 diesels, and several 521s, I have done it with normal 720s, and dually 720s/521s, I will never tow with anything except a dually ever again, it is way safer.

There are laws about what can be hauled/towed with a truck in each state.

I also have trailer brakes on my utility trailer that I have all my pressure washing equipment in, I didn't have electric brakes for years, it was very hard to stop when the truck was loaded with debris.

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I solder & heat-shrink all electrical connections. 


Just looking for a wiring kit that other Rats have had good service with on their 620.


Not much road-salt here in eastern OKlahoma and I don't drive the old timer toys in rain, snow,etc unless I get caught out in it.


Kinda like sendin' yer gandma off to work in the coal mines (this was a coal mining area 1872-1930-ish).

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Here's a '79 wiring diagram courtesy of Phixius... It should be close to a '78.  The stock wiring supports 4-wire trailer lighting Ground, Parking, Right turn/Stop, Left turn/Stop).  Typical lighting for a trailer sized for the Datsun will use a 4-wire flat plug.  So all you really need is some wire and a plug to match your trailer.


I like these Express Seal (16-14) Weatherproof Butt Splice Connectors ($4.65 for 10).

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You need a 5 to 4 converter  like this, if you try to wire in directly you'll have crossfeed issues and be chasing gremlins for quite a while.  Search for a local / better deal, I used this because iboat had a hella sale on them a few years ago and I bought some then.  They are pretty light duty so don't festoon your trailer with excess lights, would probably last forever with led trailer lights, and your flasher will last longer.

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