Having a strange issue with my Tekin rs.

Went to power it up today (soldered new leads on). Plugged in the 2s lipo, turned it on and nothing happened (no lights, sound, blinks etc). The on off switch is clean, all solder points are solid, battery is charged etc. So this is where it gets odd. I start to remove the esc from the truck, unsolder the leads from the motor (sonic 10.5). Once it is all disconnected I decide to hit the on off switch one more time. For some reason now it has power (blinking solid red).

What would cause it to not power up when soldered to the motor yet once it's all disconnected, it turns on as it should... It was connected properly, a-a, b-b etc.

Thanks in advance.