Can you get in a steam room if you have a pacemaker?

Yes. The risk of a steam room has to do with blood pressure falling as one's blood vessels dilate in the heat. Therefore, if one drinks plenty of fluids prior to entering a steam room and if one limits the time in the room to a few minutes, the likelihood of fainting due to a low BP is minimized.
Pacer. The physiology associated with the pacemaker informs the risk of a steam room. It is not the same for all.