Truck will not crank without assistance

[henbo]

I just replaced the alternator today because it tested bad (diode). The truck will not crank without using my jump starter. I also had the battery checked out and it tested good. I seem to have a problem with my ignition not working correctly. When I put in the key sometimes it is not straight in the ignition. The other issue is that my doom light comes on if I have the jump starter connected, but if take it off after the truck is cranked and kill it. The truck will not turn over and the doom light does not come on. Any help would be greatly appreciated. Sorry for such a long thread. I am trying to be detailed because I want you to know all I have done so far.

 

[Tulsa Time]

Check the connections at each end of the battery cables. Sounds like a loose connection.

 

[adsm08]

Hmm. If the doom light is on that indicates imminent, life threatening danger.

I agree with Tulsa about the root cause though. Clean your battery terminals with a terminal cleaning brush.