car randomly wont crank. alternator, starter and battery good

Check if battery is charged o rule out bad battery. A good voltage while the car is off and has not been running for a few hours (idle voltage) is ~>=12.8V. Anything above 12.3 V is okay. Does any other high current load work well (headlights, rear defrost, fans .. while the engine is not running? What happens when you turn the key? Do the dashboard lights stay bright ? Is there any noise indicating the solenoid engages or starter try to turn ?

Rule out faulty relais, fuse, voltage drop on cables, conenctors etc.: Check the voltage on the solenoid itself while you turn the key to crank. If the voltage is close to the idle voltage the solenoid does not engage.

Same issue.. Changed the starter and solenoid. Worked perfectly and the car is fixed.

Parasitic drain? Turn key off. Take oft positive battery cable. Take a DVOM and use the Amps setting. Plug the red lead into the meter's Amps terminal and the black lead in the common ( or ground ) terminal. Clip the black lead to the disconnected positive battery cable and the red lead to the positive battery post. I would hope not to have more than 300mA of current present. I think a half of an Amp is too much.

My 2006 pontiac grand prix was fine n then all of a sudden heard a ticking noise coming from the glove box n then found 3 wires in a component red black n red wires arent connected underneath the dash is that y if wont start

- suggestions to remove, clean and tighten all cables are always good especially in these high current connections.

- sometimes a trick to check if it is the solenoid is to have one person be in car and turn the key and then hit the solenoid with a heavy tool like a hammer- not too hard. This can loosen it. Sometimes it is not moving its core due to rust and dirt or its actually too weak because of too much voltage drop (see 1*)

or another trick to see if it is the solenoid/cable is to bypass the ignition:

shorten the connection from the positive cable of the solenoid to the starter. This can be dangerous because there is no fuse on the starter wire and a short to ground (any metal part in the engine compartment ) can cause high current to melt your tool. Also this bypasses the safety in newer cars that when not in neutral or parking the starter will move the car.

Assuming the starter has a good connection to the battery you will bypass any relais, loose wires, ignition switches (My dad did this with a large screwdriver or other metal tool.

In most cases if you found out that it is the solenoid try to replace only that one if possible.

03 murano same trouble it was starter relay in fuse box was corroded

Mine was the ignition fuse….

I have a 2016 Hyundai Elantra . I replaced the ignition switch , starter , battery & the alternator reads perfect . My car will only start & run with a hot shot . Once I turn the car off I need another hot shot in order to get it started . I can’t figure out what’s wrong . Lights on dash light up when you put key in ignition . It just clicks if it’s not connected to a hot shot . It can’t start on its own . Please help me

If it clicks only, the magneto does not engage properly. This switch has two functions:

1. engage the starter with the engine (like a clutch) - mechanical task

2. provide high amp current from the battery - electrical task

Often the magneto is rusted and does not move enough, or its contacts are corroded.
First line of defense: Use a hammer or heavy object to kick the magneto while cranking (2nd person required)
You may use WD40 as well, should not harm.
There is also another test that requires shorting/bypassing a connection. Requires knowledge and safety precautions.