The dishwasher will start the cycle and the timer will count down to around 47 - 42 minutes left. It will just stay in the rinse cycle and never move forward. Would this be a controller issue, or could it be a heater element issue?
Here are your parts
Replacement parts for WHIRLPOOL GU1500XTLS2 | AppliancePartsPros.com
Here is a service manual and a tech sheet
https://secured.whirlpool.com/Service/SrvTechAdm.nsf/2cd44500d572193285256a45004fd9d6/52521bdbd0ef763c85256cbc00520548/$FILE/8178022.pdf
https://www.servicematters.com/docs/wiring/Tech%20Sheet%20-%208537797.pdf
Yes it sounds like it may be a heater or a soil sense problem.
You will have to check the timing diagram to see what the unit is waiting for at that time, this of course depends on the cycle type you are using.
The heater and the Hi-Limit thermostat are easy to check with a meter.