If starter relay is not working, will the rest of the car still be eclectrfried

The first thing you must do is check for fuel delivery, you may have run out of gas even if the gage says there is fuel in it.

It sounds as if your Ignition switch is damaged, or, you have a bad relay that is sticking. To check the Ign. Switch, remove the covers on the steering column to gain access to the switch, unplug it and the engine should stop, when it's running. If it's just cranking, it should stop when you unplug the switch. If it does, then the switch is the problem. The relays you'll have to troubleshoot individually with a test light.

If only the starter continues to crank after shutting down, then you need to test the solenoid on the starter as well as the starter relays and the Ign. switch to determine which is causing the current to continue to the starter.

IT IS LOOKS LIKE A FUEL PRESSURE LEAKING INSIDE THE ENGINE OR DEFECTIVE FUEL INJECTOR LEAKING . TRY DISCONNECTING THE FUEL PUMP RELAY. AND CRANK THE ENGINE IF ALWAYS CRANK WITH OUT OF FUEL (CRANK WITHOUT START) YOU HAVE FUEL LEAK INSIDE THE ENGINE
REMOVE THE INJECTORS RAIL UP EVERYTHING CONNECTED,PUT BACK THE FUEL PUMP RELAY TURN THE SWITCH ON AND FIND WICH ONE IS LEAKING. (GASOLINE IS FLAMMABLE TAKE CARE)

Starter motor relay , transmission range switch , wiring ! Do you know what a wiring diagram is ? How to read one ? How to use a DVOM - digital volt ohm meter ?
How to voltage drop test starter motor circuit
do you know what a relay is ? how to test one .
VEHICLE RELAYS Operation Diagnosis
You can view free wiring diagrams here http://www.bbbind.com/free_tsb.html enter the vehicle info. year , make , model , engine size . Under system click on engine , then under sub system click on charging system . click search button ,one link will pop up , click on it . First diagram is starter circuir . If starts jumping at the starter the problem is on the control side . trans range switch , starter relay ,blown # 6 40 amp fuse in the under hood fuse / relay center .

Yes it could be the switch.
Or something in the engine compartment.

check for proper current from alternator more than13.5 volts that should do it if not check active codes if its not stolen

I would say your starter is faulty. Since the vehicle runs fine, and doesn't start up after being shut off until it has cooled down, it sounds more like a starter that loses contact when it is hot. You could check the starter terminals for 12 volts using a multimeter when the key is turned to Start the engine after warming up the engine and shutting it off. If 12 volts are present, replace the starter. If 12 volts are not present, check the Starter relay.

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

Hi, this is what you should do when your car won't start. Diagnosing a no-start condition requires a logical approach to figuring out what might be preventing your car from starting. First, if the engine won't even crank over when you turn the ignition to START, your car obviously won't start.
When you turn the ignition key to start your car, voltage from the battery flows through the ignition switch to the Park/Neutral safety switch and/or brake pedal or clutch pedal safety switch (you have to push the pedal down before the circuit will complete) to the starter relay or solenoid. When the relay or solenoid is energized by voltage from the ignition switch circuit, it closes a contact that routes more power from the battery directly to the starter to crank the engine. The starter motor spins, pushes the starter drive gear to engage the flywheel and cranks the engine.

If the engine fails to crank, there is a fault in one of the components in the battery/ignition/starter circuit. Check it out.....

• Low battery (Check battery voltage, recharge if low, or jump start with another vehicle or battery charger).
• Loose or corroded battery cables (Inspect, clean and tighten BOTH ends of BOTH battery cables).
• Bad starter relay wiring connections or ground connection (Inspect, clean, tighten wiring connections).
• Bad starter relay/solenoid (Check for voltage at relay, if relay has voltage but there is no "click" when key is turned to start, replace relay).
• Bad starter (Jump battery voltage direct to starter to see if it spins, or remove starter and have it bench tested at auto parts store).
• Damaged starter drive or teeth on flywheel (Remove starter and inspect drive gear and flywheel teeth, replace damaged parts if necessary).
• Bad ignition switch (Check to see if voltage reaches starter relay/solenoid when turn to start. If not, check for open P/N switch and brake or clutch pedal switch. Replace ignition switch if defective).
• Open P/N safety switch, or open Brake Pedal Safety Switch (automatic transmission) or open Clutch Pedal Switch (manual transmission). Bypass switch with jumper wire to see if engine cranks, or use test light or voltmeter to check for voltage passing through switch when ignition is turned to start.
• Engine seized due to bearing failure or internal damage (Use socket and long handle to see if engine can be turned by hand, if not engine is locked up).
• Engine hydrolocked due to coolant leak from leaky head gasket (Use socket and wrench to see if engine rotates, remove spark plugs and see if coolant comes out or engine can not be cranked with plugs out).

When you turn the ignition key to start your car, voltage from the battery flows through the ignition switch to the Park/Neutral safety switch and/or brake pedal or clutch pedal safety switch (you have to push the pedal down before the circuit will complete) to the starter relay or solenoid. When the relay or solenoid is energized by voltage from the ignition switch circuit, it closes a contact that routes more power from the battery directly to the starter to crank the engine. The starter motor spins, pushes the starter drive gear to engage the flywheel and cranks the engine.

Low battery (Check battery voltage, recharge if low, or jump start with another vehicle or battery charger).
Loose or corroded battery cables (Inspect, clean and tighten BOTH ends of BOTH battery cables).
Bad starter relay wiring connections or ground connection (Inspect, clean, tighten wiring connections).
Bad starter relay/solenoid (Check for voltage at relay, if relay has voltage but there is no "click" when key is turned to start, replace relay).
Bad starter (Jump battery voltage direct to starter to see if it spins, or remove starter and have it bench tested at auto parts store).
Damaged starter drive or teeth on flywheel (Remove starter and inspect drive gear and flywheel teeth, replace damaged parts if necessary).
Bad ignition switch (Check to see if voltage reaches starter relay/solenoid when turn to start. If not, check for open P/N switch and brake or clutch pedal switch. Replace ignition switch if defective).
Open P/N safety switch, or open Brake Pedal Safety Switch (automatic transmission) or open Clutch Pedal Switch (manual transmission). Bypass switch with jumper wire to see if engine cranks, or use test light or voltmeter to check for voltage passing through switch when ignition is turned to start.
Engine seized due to bearing failure or internal damage (Use socket and long handle to see if engine can be turned by hand, if not engine is locked up).
Engine hydrolocked due to coolant leak from leaky head gasket (Use socket and wrench to see if engine rotates, remove spark plugs and see if coolant comes out or engine can not be cranked with plugs out).