What size/gauge wire did you use? Example: a 16 ga wire will carry 12A max. A 14ga will carry 15A. (conservatively using 140-F degree temps that are common in automotive use)
(easy way to check…. read the label on your typical extension cords)
It would take an 10ga wire to carry 30A…. which is larger ga. than typical house-wiring circuits.
You do NOT want to burn up your tractor’s wiring harness…and using a 30A fuse on 14ga wire will risk that.
It would be better to run individual wires to each LED/light… OR… use a relay/solenoid to supply all 4 with only one switch….(each relay also protected by a fuse of appropriate size.)
Here’s a convenient chart to help determine wire gauge VS amps:
Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.
www.cerrowire.com