Car wont start

Maybe you need to do voltage drop test, battery connections and starter motor connections? Any testing at starter, make sure transmission is in park or neutral and parking brake is set. Vehicle can't move. You can use digital multimeter at each end of battery cable, take reading with circuit under load. The reading on both ends should close to the same, if big voltage difference between ends, replace the cable, any cable. Give the starter motor time to cool off between cranking. Just my opinion.