Had the same problem yesterday. Went through the Suburban trouble shooting guide and it appears I have a bad element. You should have 14.5 - 17 ohms on the element and mine is 10.5. Now to see if Jayco will send me a new element. Ours is also in a Pinnacle and have only been using it for two months.
Retired Firefighter, Full Time RVer, 2011 36REQS Pinnacle, dragged by 2005 Dodge 3500 DW.