Removing redundant lines from script
This is what I would do.

First, rename coordinates to coord_list so you can eliminate mylist which is kind of useless since you only use immediately assign it to coordinates. To make things slightly simpler I assigned count to coord_list.Count so now you can just check count instead of coord_list.Count. Instead of executing the loop if the Count is bad, we check that count is between 1 and 3  before entering the loop. From here it loops though the activeDataConnections and has been changed so it checks count instead of repetition of the same logic.

Here is the code:

def getTableGroupTopMember_Test1(coord_list):
    '''
    Depending on the number of coordinates given, this function/code returns a unique coordinate. 
    '''
    count = coord_list.Count

    # thanks to 200_success
    if not 0 &lt; count &lt; 4:
        print "your code is shit!"
        return

    for adc in activeDataConnections:
        for table in adc:
            if table.Name == coord_list[0] and count == 1:
                print "/"
            elif table.Name == coord_list[0]:
                for topgroup in table.TopAxis.Groups:
                    if topgroup.Name == coord_list[1] and count == 2:
                        print topgroup.Address
                    elif topgroup.Name == coord_list[1]:
                        for topmember in topgroup:
                            if topmember.Name == coord_list[2]:
                                print topmember.Address



getTableGroupTopMember_Test1(["Table10"])
getTableGroupTopMember_Test1(["Table10", "profile_julesage",])
getTableGroupTopMember_Test1(["Table10", "profile_julesage", "_25_to_34"])