Need to no where the rear windscreen relay swicth

Hi Jim. I recommend checking the electrical portion of the ignition switch. It is responsible for supplying power to many consumers, and is known for causing mysterious air bag lights and 4x4 lights. The switch is relatively inexpensive and not very difficult to replace.

wiper relay is in the Ebox in the right rear engine compartment.
rain sensor is in the center windshield behind the rearview mirror

F81 fuse in rear cargo compartment
F41 fuse above glove box
K11 module in E-box right rear engine compartment
If these all work replace the wiper motor.

try this link might help you out.
https://www.google.co.uk/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=bmw+x5+2004+rear+wiper+isn%27t+working

pull the wiper handle (right side of steering column) toward you.

Check power to the wiper .if no power might be the actual motor.

It is in the Glove box. there is a drop down panel in there on top with 2 pins that holds it in.

Hi in glove box pozition 1 30A windscreen wiper motor relay.

Don't drive to any rough areas. Especially if it's raining. HTH.