Hi DJ, thanks for your response, I was aware of the back EMF issues, though wondered if the diode was to protect the ECU from the coil, or the contacts in the relay from the back EMF when the pump was switched off..
Colin, in all my years of blowing things up with AC and DC, I never came across anyone or anything that suggested breaking the DC Negative created less of a spark....Duh..! As they say, every day is a school day, thanks for the education chum.. and look after yourself WELL..
