Fuse # 15 bowing -- Please help

[MJ Hedstrom]

Fuse #15 on my son's 1990 Audi 100 keeps blowing. The problem seems
to be
related to the wipers. The 25 amp fuse has the following items on the
circut according to owner's manual: wiper motor, turn signals, air
conditioner, washing nozzle heating, thermoswitch for radiator fan.

Here's what we done and know:

1) Is not motor or binding. Confirmed by diconnecting the wire connection
at motor. Fuse still blows.

2) The fuse only blows when the car is placed in gear. Confirmed by
running wiper with car started and in park. Even added the additional load
of ACand turn signals (both are also on this fuse) and as long as the car
was in park the fuse did not blow.

3) Put the car in gear and it blows in short order (no pun intended).

4) The previous owner had replaced the wiper motor and relay in the past
year

Members help and insights would be most appreciated. Thanks