Many basic UK Indesit washing machines fitted with a rotary dial indicate error codes by clicking the dial continuously round and flashing the door lock light a set number of times.
If the door light (LED) flashes 7 times it means, “Heater relay stuck – check connections on heater and module (PCB)”.
In my experience, this fault code usually required a replacement PCB and EEProm. A connection fault on the heater usually results in the entire washing machine going dead. Nothing will work, but the LEDs light up. This symptom can also be caused by an open circuit motor or other faults.
It’s always possible for a connection fault to cause error codes but the heater relay is embedded in the PCB and if it develops a fault the whole board needs replacing. I don’t recommend replacing the PCB as a DIY repair. It is an expensive part and it will not be guaranteed unless fitted by an engineer. New PCBs do not come with the micro-chip EEPROM which would also need fitting. Replacing the PCB and EEPROM yourself is risky. If the fault is not cured you cannot send the parts back.
If you have an engineer to replace the PCB and EEPROM I would imagine the cost is likely to easily be over £100. If your washing machine has a 5 year parts guarantee Indesit would supply the PCB free of charge but only if their own engineer fits it at a cost of about £90.
If you are really keen to fix this yourself and want to try another PCB there is a company that might be able to help. They are happy to deal with the general public as well as trade. Try QER (Quality Electronic Repairs).