My daughter's 99 grand prix stopped blowing heat. The blower is not engaging on any speed. We pulled the blower, jumped it from the battery and it blows fine. tested the plug that goes into the blower and that also reads 13.9 amps on speeds 3&4, not 1,2 or 5. cleaned the connections, not sure what to test next. ignition or resistor or ? Seems like the blower should still engage on speeds 3 & 4 but it does not. Thanks