"...if it is electrical it is in the wiring from the button to the relay...sound logical to you?"

I think it's more likely the wire feeding steady +12 from fuse 12 to the relay, or intermittent contact at the fuse. The wire (blue/red) goes straight from the fuse to the relay (terminal 15)**

The push button switch is normally open, and only "pulses" the relay to make it "toggle" On or OFF.

And the relay coil ground must be OK as it is allowing the Arrow light to come on when the relay is OFF (a common shared ground wire). The other side of the light is tied to +12V.

**Diagnostic Relay Bypass**
In the hope that the wiring to the solenoid (and the solenoid) are OK, you can try bypassing the relay by inserting a simple jumper wire in its place.

1) Locate and remove the relay from the rack behind the fuses.

2) Identify relay terminals 15 and 87, on the bottom of the relay.

3) Carefully relate those two terminals to their respective relay rack sockets.

4) Insert the Jumper Wire* to connect the sockets for terminals 15 and 87.

5) The effect will be that of an OD relay that is always ON.

* A good-fitting jumper can be made with flat male crimp-on terminals that are the same size and shape as the relay terminals. Use the BLUE insulated crimp terminals with a snug-fitting wire (#16 or #18 I think).