Whirlpool AWM330 857033015100 W/M heating problem

Hi to all you brainy peeps who have had all these problems B4

Customer complains water not heating, unless she uses programme 3 Delicates, and sets rotary temperature control to 95c

Ok so set machine on programe 3 and temperature to 50c
Switch on, fills and then starts to heat, but only for about 3 to 4 minutes, then stops heating and presumably would carry on through programme.

Tried again at 60c still the same and measured water temp in tub to be just 30c.

The thermostat, just an ordinary capilliary type is still calling for heat, ie still closed contacts, when machine aborts the heating.

Can only assume its timer/pcb assembly.

Unless of course you know different?? Any suggestions appreciated PLEASE

Malc