It's a goodman furnace. It has a 3 amp fuse in it. Every time it gets replaced it blows once turned on. I have replaced the thermostat and checked all the wires. I need help. What can I do

Usually the fuse blowing is due to a short circuit in the low voltage wiring or a defective component. You will need to use normal service procedures and eliminate each item on the furnace or wiring one at a time to discover the defective/shorted part or wire.

My bryant furnace occasionally would blow the 3 amp fuse on the circuit board.
I found the themostat wire rubbed through laying on top of sheetmetal ductwork.
The red wire had a tiny burn mark. A closer look and I could see bare wire. I pulled the wire away from ductwork so it can't touch anymore. Taped up wire with electric tape. Problem solved. No more blown 3 amp fuses.