It could be a sensor or a wiring fault,as it is intrmittent i would get the car in for a diagnostic check,you could replace half the engine before you find the fault,sorry cant be more help.vbnm247 said:Hi. I am posting this on behalf of my friend who is having a problem with a peugeot 306 but does not have the internet.
The car is a peugeot 306 19td diesel.
When the heater and the rear screen heater is switched on the headlights dip as if they are going off and the fan heater goes up then down. It does not happen every time which has made it hard to find the cause.
He has changed the altinator but it still happens. Has anyone came accross this sort of problem before?
Any advice would be appreciated.