Transponder uses about 60 milliamps as I recall and 5 amps would turn it to good BBQ charcoal.
IF you can find one about your best shot at saving it from a short circuit is 0.5 amp if you can find it.
When we 1st did ours, we put a 1 amp fuse in which was the smallest I could find. Second time we wired it, we just connected it to the ignition switch
The heck with it if it can't take a joke!
Yes, I know, AMB says to put it in a fused circuit. But, they don't tell you what size or provide the 12 cent fuse. Duhhh
It's their way of being sure if you cook it all they say is.. well, you didn't have the right size fuse in there did you?