Only tasting will tell and time may fix it. I recently discovered my temp sensor was off by 15F, meaning I was fermenting in the 80'sF. You may be just fine depending on when your temp control stopped working, if you got any amount of control early on that should help a bit. You are likely to get some more esters but as long as you don't get fusel alcohols the high temp shouldn't kill your beer. I've never made a dunkleweizen but I would think that style could handle extra esters more than others anyway. Taste it, if it taste fine you are good to go, if you have a slight banana or bubblegum flavor you've got a bit more esters in the beer than planned, which may be just fine, if it taste solvent like you may have a lot of esters. Either way if you don't like it let it sit for a while, though it may be a long time if it is solvent like.
