Punto 90 ELX Cabriolet-Diagnostic Plug

Hi,I had a new alternator fitted a couple of weeks ago.Since then the fuel ignition warning light is on all the time,and she is using a lot of petrol.The mechanic who fitted the alternator has looked but can't find out why,he took it too a diagnostic centre but they can't find the plug/socket thing to connect to.Apparantely it should be down by the hand brake but mine is blanked off.Does anyone know where it is on the cabriolet,please?

the ecu is under the centre of the dash so if you remove the centre console and look at the multi plugs for it there should be a small 3 core wire going to the plug

if not it's under the bonnet somewhere

Thank you,found it under the bonnet.