I had a similar fault, car would not start, wipers on, all sorts of things displayed on the dashboard, lights on , engine fan running flat out etc only way to stop various things such as wipers going was to disconnect the battery.
I know a very good auto electrician ex Renault employee . Came to look at the car - I feared the worse and a large bill but within 30 minutes he had traced to to a broken wire on the wiring that goes to the engine ECU
(located near the battery)
Repaired broken wire and all fixed.Charged me £50 - he has travelled 35 miles to get to me!