Originally Posted by bdl99

But you agree that the blue arrow is an input to the CPU and it won't be hot without the fuse? It wouldn't be an indication of the steering lock status because it would always be hot as long as the relay was activated which the CPU already knows because it triggers the relay via the earth/ground feed above the blue arrow and the status of the lock is communicated by the other wires going from the steering lock to the CPU. As I said it is great that there appears to be no down sides, but it is also unusual for a circuit to include a feed like that if it isn't used. It could simply be for the CPU to know that the activation of the relay was successful, but without seeing the inside of the CPU or having access to the code there would be no way of knowing for sure.