miofan

Hi I had a big problem with my w203.208 220cdi '04 model, The car had an issue with at gearbox control module, I changed it, all code erased, tested no more faulty codes but the car wont crank, wont start. Tried my second key, same result. How can I check the starter relay, before try to change the starter soleonid or starter motor. I hear from the engine bay, the ac pump whinning, so possible the fuel line is ok. I was by petrol staion and fuelled full the tank, than happened the starting problem.