Hotpoint WDL520G lights flashing

i have a horpoint washer dryer here wdl520 and when i am doing a fast wash (5) the horizontal lights are all flickering and the vertical lights spin, dry, and lock light are on when the cycle is coming to an end and moving onto the drying stage. i read some where on this that it is a f13 fault which the condenser is blocked….would this be the case or am i looking at something more troublesome i.e. pcb? A second opinion would be grateful