521 wiring

[Guest Rick-rat]

 I am in desperate need of help to get the wiring on my 521 working properly, one taillight not working, rear side markers not working, no turn signals, fuel gauge and water temp gauge not working. Any one in the Gig Harbor area that can assist?

[MicroMachinery]

Truck should still be under warranty...

[Draker]

Does the cluster have the voltage regulator attached?

[Guest Rick-rat]

I don't know

[uberkevin]

Sounds like maybe some grounds need to be hooked up.

 

Really wish I wasn't stupid busy. I'd come help you out.

I'll see if I can come up Saturday, I'll let you know.

[DanielC]

I worked on the some of the electrical on your truck.  I tested the tail lights, and rear marker lights on a bench, with a rear harness.  I believe the harness I tested the rear lights was not used, another harness was, that was already on the chassis.

 

The rear side marker lights on a 521 ground to the frame of the truck.  There should be a black wire, coming out of the harness, on both sides, that go to the frame of the truck.  Check that. 

 

The tail light assemblies have a ground in each assembly harness, that connects to the frame of the tail light assembly.  Originally, a 521 depends on the bed, or box being grounded to ground the tail light frame.   Adding an extra ground wire from the tail light assembly frame, to the frame of the truck is sometimes needed.   

 

If you ground the temperature sensor wire, the temp gauge should go full hot.

If you connect the two wires that attach to the fuel tank sender, or top of the gas tank, the fuel gauge should go to Full.

 

This is a picture of the pins on the 521 instrument cluster.

 

If you remove the instrument cluster from the truck, connect 12 volts positive to the IGN power in, and 12 volts negative to the ground pin.   Then grounding the fuel sender pin, or the temp sender pin will cause that gauge to to full scale.

[Guest Rick-rat]

No wires even going to the gas tank sending unit, doesn't even look like there is a place to connect them no wires to the pass side marker lights, the wiring to the tail lights and marker lights has been hackep up. Horn still honks when the ign switch is turned to start, unplugged at the moment

[DanielC]

Denmarkboy may still have the harness I tested the rear lights with.  One of the tests I did was to plug the tail lights, and marker lights into the harness, and apply power to the connector that is normally below the fusebox, close to the starter when it is installed in a 521.  I think I remember that harness having the fuel tank hook up. 

 

Later I will take a look under one of my 521 trucks, and see where the fuel tank sender wires branch off the rear harness.

[bananahamuck]

What year is the actual truck?? , The build thread says 70,, but i know they were going to use another truck at first,, so i don't know if title changed to reflect that or not.

 

I ask because,,,  JJ has a couple huge wiring diagrams copied onto sheets of plastic 3' x 4'  (at least)  that he might be able to loan you,  that might make guessing easier than sticking yur nose in a book over and over.  but only has certain years.

[DanielC]

The truck got put together with parts from different years of 521 trucks.  The original wiring harness was too chewed up to be easily usable.

This truck first came to Ratsun as "rabbit pen".

MKlotz70 donated a good wiring harness, that I suspect came from a 1972 521, because it had what I believe was an electric choke relay.