I recently obtained an RX7 and was told it worked fine but would not start due to the clutch going out while it was sitting some wires near the alternator were chewed by rats too, so after the wires and the clutch were all fixed I went to try to start it it won't turn over. When I connect the battery to it and turn the key I hear a loud buzzing sound coming from the engine bay, somewhere near the alternator, all the error and warning lights up on the dashboard also light up and a shift up light comes on the dash. If I turn the heater on the buzz goes away, but when I go to turn the key nothing turns over at all.
The engine does turn over freely, I tried by hand.
I will be checking for fuses/power tomorrow, and may be able to read an ecu error code if there are any, but I as wondering if anybody knew what could be causing this problem, thank you for any help!