on the W210 I changed the fuel filter filled it and put it back and car wont start it coughed for a little but wont turn over

I hear a click under hood when key is turned over battery got weak and need to be either replaced or charged now


If I have to bleed the lines where to I crack them open ? right out the pump ? or under the black cover where they go into the engine ?

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2003 GX470
1998 E300 3.0TD
2002 Dodge 2500 4x4 cummins
1998 Dodge 3500 5 speed Cummins