Perhaps you could post a little more information on your Weimie, like how old is the dog?, gender?, how long have you had him/her?, any recent changes in household?, etc.
Sleep wetting (aka enuresis), can generally be categorized as either organic (i.e., a specific medical problem), or behavioral.
The first thing you would like to rule-out is some organic cause. For example, in older male dogs, it could be a prostate problem. Another cause might be bladder stones, or a chronic urinary tract infection, etc.
Once all organic causes are eliminated, then one could consider behavioral issues. A friend of ours had a dog with this problem, brought on by their eldest child leaving home to go off to college. When the child was home, problem stopped. Eventually, the problem resolved. Sometimes, vets will prescribe anti-anxiety or anti-depression meds short-term if the cause is identified as behavioral in origin.
Maybe with more information, other TBNers could add more to help...