Ge dish water not hot enough

The water in my dishwater does not seem to be hot enough.Have checked the temp.coming from tap & it is 130 deg F,ran wash cycle for 2-3 min. then opened the door & checked again, found temp to be only 105 deg F.I have put tester on heating element & there is power on the element thru the wash cycle,& the plate warming is plenty hot enough.Is there something else I need to check & where can I locate a print to show me where other parts are located & how to check & replace.Thanks Dave
Serial # is VR601806A