Determine whether it is an oil pressure alarm or an overheat alarm. Carefully disconnect one and start the engine.. if it still alarms, reconnect that one and disconnect the other one.. It is not unusual for an oil pressure switch to fail and start sounding a false alarm; do not assume it is bad and leave it disconnected .. a mechanic can check the oil pressure and verify or, if it is the oil pressure switch, you can buy one and replace it .. Same with the temperature switch easy to replace and fairly inexpensive. Some engine panels have a battery charge alarm .. if that is the case and yours is sounding, check that all the belts are tight .. if they are, then its time to use a voltmeter to check that side of the system. You should see above 13 Volts DC if the alternator is working.. Good Luck