John Janssen

Have a 04 sprinter that we were checking continuity of wiring harness with test light connected to battery under the hood at sensors unplugged, with ecm unplugged grounding connector pins to see to check for continuity when light came on. seemed all wiring ok. then plugged in ecm and no start had crank but the fuel pump relay only comes on for split second, so im thinking some input into ecm is not satisfying ecm to say lets start, could we have back fed something for this to happen, van ran before we did this harness check because of other issues. any ideas are much needed thanks John