I just picked up a 2003 Prairie 650 from my stepdad. It has not been used very much, but has been sitting in the garage for about 20 years.

My stepdad purchased a new battery for it the other day and accidentally hooked it up backwards. That ended up blowing the main fuse and resulted in no electrical power. I replaced the 30A main fuse and power returned, however the orange fuel light and the red oil light on the dash panel are now flashing. Code? The fuel level reading is also zero, and the fuel pump is not activating. No fuel moving through the fuel line. The starter is working and the engine is turning over.

I'm assuming this is likely an electrical issue, and a decent chance it's from the backwards battery installation. But I guess it could be from corrosion after 20 years of sitting.

I have a multi meter. I can't say I'm an expert on how to use it, but I follow instruction well. If I'm hooking it up correctly, it looks like 2 pins at the fuel pump connection are reading 12V. It's the blue and brown wires. I also tried resetting the ECU (pulled ECU out, turned on ignition, turned off ignition, then reinstalled ECU). Tried turning on again but the lights were still flashing and no change with the fuel level reading or fuel pump activity.
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​​​​​Any advice on where to start is much appreciated!!!