Radio Wiring, Part One

I took the two PG-20 harnesses for the TS-480HX and the extended wiring harness from the PG-5F for the TM-D710G, and stuffed them into a 20′ wire 3/4″ wire loom. They take up the entire loom but it does close around them and I ran 4″ zip ties approximately every 4″ along the loom. I left the connectors to the radios sticking out several inches.


I purchased some inexpensive relays off Amazon. I found that the sockets are wired backwards – red is negative and black is positive, but otherwise work as expected. Yellow goes to trigger and blue goes to the radio. I chopped off the white which could be used for a second device. I’m going to be using ~25A of the 30A capacity on each of these. The purpose of using the relays here is that I can pull power directly from the battery but enable/disable it with external triggers.


I used heat shrink tubing to terminate and protect the connections instead of electrical tape. This example is the blue (output to device) from the relay joining the positive to the radio. I’m going to be using these throughout the rest of the install as well.


The finished harness, ready to install. It will be ran from the engine compartment, under the truck along the frame rail, and into the vent between the cab and the bed. The radios will be mounted under the back seat right by where the wires come in.


For the ignition trigger, I bought a micro fuse tap off Amazon and joined it to a spare red wire from my light install. I tapped into the “Misc. Ign” with a 5A fuse and ran it across the back of the engine compartment to the passenger side where it connects to a 3A inline diode. The yellow wires from the relay harnesses will connect to the striped side of the diode. The override switch will go into another diode also connected to the yellow wires. The diodes will allow me to use two trigger sources on the relays without one trigger sending voltage to the other. I tested this tonight with my multi-meter and it works great.

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