how do i put a led across a fuse
Use a current divider placed after the fuse.
A current divider is very simple. You set the 2mA curent flowing into a resistor R1 and LED, and 8mA into a resistor R2 of a smaller value.
In this way, both current paths maintain a common node of 3V potential difference, which is needed to drive the LED in series with R1 because LED usually requires 2.2V for Red, 1.9V for Green or Yellow. Do not use Blue LED because you need 2.9 to 3.4V at least.
R1 is used to provide current-limiting resistance to LED and part of the current divider parameter.
10mA = [(3V-2.2V)/R1] + [3V/R2] = 2mA + 8mA