No, it's a variation of that, but our trucks should be wired a little differently:

Disconnect the battery. Remove the small feed wire that runs from the ignition switch to the starter solenoid. Cut off the connector leaving enough wire to be able to splice it onto another wire later. Splice the cut end of the wire (the one you just cut) coming from the ignition switch and run the extended wire up to the small trigger terminal on the new solenoid. Run a wire from the battery (+) to one of the larger side posts on the new solenoid. From the other large post of the new solenoid run a wire back down and splice it into the connector that triggers the starter solenoid. Neaten up the wiring, reconnect your battery and you're readu to go.

All wiring connections should be crimped, soldered and covered with shrink tube - the kind with the hot melt adhesive inside so they'll be weatherproof. For splices, push or cut the inner metal tube out of the plastic butt connector sleeve and use just the metal part so you can solder it.... same on the ring connectors - pull off the plastic and use just the metal... after crimping and soldering you'll heat the pre-applied shrink tubing which will do a lot better job than the plastic covers. I find the best way to solder them is with a butane torch - be sure to use resin core electrical solder - not the acid core plumbing variety. Wire size isn't terribly critical - I'd choose one size larger than the OE wire coming from the key switch to the starter but I have forgotten what size it is.

The above instructions assume a case grounded relay. Case grounded and isolated are both made. If you get a 4-terminal (like the one in the picture) it's ok - you only need to use one of the small trigger terminals as long as you mount the solenoid on a grounded point like the fender - as you can see, I made a stainless steel bracket and stacked it on top of the power steering reservoir mount.

I'd also suggest testing your key switch for proper voltage - cycle the key switch several times to see several readings. You can do it before or after you install the new relay - for before: disconnect the wire coming from the key switch at the starter solenoid and probe the connector while someone turns and holds the key in the "START" position - for after: disconnect the trigger wire to the new solenoid relay and have someone do the same with the ignition switch while you read voltage at the wire end. If you don't get full battery voltage you have a wiring problem or an ignition switch problem. The electrical part of the ignition switch is an easy fix.

You can find the heat shrink tubing with adhesive at any Boater's World, E&B Marine or West Marine... they have good connector terminals and wire as well. It's a little pricier than at an auto store, but I like the quality much better.

Let us know how it works.

Frank