Why will the Van start sometimes weather its done on its own or jumped? on 1998 Dodge Ram Van 1500

Sometimes the Van starts - sometimes it doesn't weather it's either on its own or jumped.
It has a new alternator and new fuel pump.
took the battery into auto to have it fully charged. - have been using the internal plug to charge up phone.
It turned on two days ago. didn't turn on yesterday. turned on today.
any suggestions on what to check next?

Asked by for the 1998 Dodge Ram Van 1500
2 answers
I can not find answers I had same problem how did you fix. I had crank shaft senser and computer replaced no help waste of money please help my email is hawaiifarm82@gmail thank you for any help
either the ground wire or the hot wire is probably loose on your starter but it can also be loose and/or battery terminals, your ignition switch or your solenoid.. most likely it is something not connected tightly as it should be :).