Vauxhall Zafira A - fans running - markevans

my 2001 zafira has the coolant light flashing on and off on the dash board the coolant levels are ok all so when i turn on the ignition but dont start the engine the radiator fan and the ac fan starts to run when the engine is started the fans still run all so hard to start when cold but when the engine is warm it starts every time changed glow plugs and no trouble codes