Simpson Esprit 750 7.5kg won't fill with hot water?

Hi Our "Simpson Esprit 750 7.5kg Heavy Duty" top-loading, washing machine is about 12 years old. It fills with cold water, but we are wondering why IT WILL NOT FILL WITH HOT WATER? Both taps work and are definitely turned on. Could it be some kind of pump (or something) which draws hot water into the drum is faulty? As far as we can tell, the hoses are in great condition. We have never changed the seals inside the taps. We have never had a problem with ANYTHING else on this washer. It's been a brilliant performer. Thank you, we appreciate any help! :)