The wire from the temperature light control module (white module in indicator lamp housing) to the sensor is black with a green stripe (B/G). It also has its own direct wire to ground that is black/brown (B/Br).
It's possible, but unlikely. As shown in your photo, the sensor has a pin that fits a socket on the wire from the temp module, and that matches the schematic. The schematic shows a socket on the horn, and a pin on the wire from horn button. If the wire from the module could reach the wire the from the horn button, they would mate, but the horn switch is normally open, so the module wouldn't see the low resistance that would turn the lamp on, unless the switch is damaged.Had a thought. Could I have the horn B/GR wire hooked up to the one that goes to the sensor and vice versa?
That thought came to mind while I was away.