2009 Corolla Gauges and engine acting strange.

Whether parked or driving the gauges die, sometimes come back on for a second then die again, engine sputters then runs for a while at idle with intermittent throttle response then dies. The battery is not dead. The windows still go up and down and the lights are still bright. However jumping it to another car's battery will make it start again. It will run normally for about 5 minutes after disconnecting from the other car and do the same thing again. The battery/charging light does not come on. I have tested it a dozen times and same thing happens every time. The heater fan has stopped working so I disconnected it in case it is shorting the power. Made no difference. Checked all fuses and swapped out the relays, no difference. The car sat for a while with a bad fuel pump. New fuel pump is installed but now this.

I'd start by having the alternator checked. My car did all kinds of crazy stuff when the alternator went bad.

Bad diode in alternator, was only putting out 9 volts. Battery held a 12 volt charge 24 hrs but only had half it's cc amps. Replaced alternator and battery. Charging at 12.4 volts now, expected 13 plus but it stays at 12.4 with all accessories and high beams on at idle. No power to heater fan or resistor next to it and no turn signals now. Working on those.

7.5 AMP FUSE Hidden under the dash for heater fan, turn signals, and charge sense. That fixed it. Charging at 13.8 now.