Start error after replacing battery?

after 2 -4 tries on starting the unit a start error appears and then no spark I let the glow plugs warm up before each try and I do not try to start it in a rapid fire series each time I remove the key gently and put it back in after waiting 4-5 seconds and after 3 or 4 tries the error message appears along with the headlamp that was replced it only comes on when I turn the lights on while the other headlamp is on as long as the unit is running I checked the fuses and under the steering colunm and they appear to be good a s well as the dash board lights come on if I turn the unit off and my head lamps are still on but when I put the unit in gear the dash lights on the speedometer go out but are on for the temp and fan switch when the unit is in gear