When the charge is low the A/T light will come on as a warning.
It could be a sign that you alternator is on it's way out. First check that the battery connections are all fine (it's easy to leave one loose when refitting), and then put a multimeter across the batterys with the engine running, you should get a reading around 14 volts when the engine is revved up. If it's only showing around 12volts, then it'll be your alternator. It's quite common for them to go on pajeros.
Although I'm not sure why that would cause a fuse to keep blowing