Where do I look for problem

If that is the only instance to blow the fuse; when the contact key is turned 'ON' the relay sets priority to 'start engine' mode, like directing the power to the starting accessories, now when instead you activate something else, the circuit is overloaded: Puff

Once a fuse blows & you replace it-- ONE Time--
then you stop

You go to wiring diagrams of the circuit with the
blown fuse & start your testing

did u replace the relay just a curious question, sometimes they have rust and water in the inside of the relay but my guess would be that you have a bare wire rubbing somewhere, causing the fuse to blow, anything significant has happened before that issue?

A bad something, yes.
The fuse may be the primary fuse for the key switch. If it is, you would need to disconnect the key switch harness and check for a short to ground on each circuit.

Check out your tail lights, sounds like they are grounding out. Remove the bulbs install a new fuse and install one bulb back on at a time and turn the key if one does not blow the fuse then the socket has worn out.

Pull the EFI relay, replace the fuse, and see if it blows when you turn the key on. If it does not turn the key off, reinstall the EFI relay and remove the circuit opening relay/fuel pump relay. Turn the key on. If the fuse blows than we know the problem is One of the O2 sensors, the IAC, the purge solenoid, or the ECM You can unplug the O2 sensors, iac, and purge solenoid. Replace the fuse, turn the key on, and plug them in one at a time until the fuse blows. Replace that component. If the fuse blows with those unplugged than its probaly the wiring and possibly the ECM. let me know what you find and I'll help you more if needed.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

I am a mechanic,i had that same problem where my engine 20amp fuse were blowing....i fixed it...problem were a broken wire in the harnace on the side of the cylinder head....i made over $200 on that job...yahhh

It sounds like you have a short in some wiresets. Check the wires directly connected to the ignition. If this persists, without any problems with wires, I suggest checking the amperage and voltage on your battery to make sure they are at operational levels. Anything over 14.8 volts and you start to fry electrical components and... blow fuses.

Mine is doing the same thing. We are getting ready to replace the starter. Hopefully that is the problem. I'll let you know how it turns out.

It MUST be the starter relay coil - or the power wire that feeds it. Likely a short in the relay coil (AKA starter selenoid).