John
I note your ?? After the comment about ECU picking up the relay earths. This is not at all uncommon ECU’s are often used to switch on and off earths to components as it’s much cooler to switch on earth on and off than feeds.
Heat is the enemy of control modules so manufacturers soon learnt to use the ECU to switch earths on and off this is the case with fuel injection on Motronic systems for example. Less arcing and all that ;-)
BR
Colin
