Rear Window Power Issue?
 

Evening Folks,

This is a bit of a head Scratcher. 2004 WRX Blobeye

Rear driver side passenger window switch was not operating the window up or down, I took apart the switch and the previous owner did not leave many bits inside so I ordered a replacement

Fitted new switch and window will only go down. I tested the motor with direct power and its fine, up and down no issue
I removed the passenger side switch which is operating its own window perfect but will only put that window down also
Motor Fine / Switch Fine / But window will only go down ?

Please note the drivers control will not work that window in either direction / Replacement switch ordered also

Anybody any Suggestions, Thanks

Something to look at attached
You may have a broken link wire between master and slave switches for the right rear window (colour code LW - blue/white)

Before all this occurred did you notice a difference in the speed of the windows movement ?

Although you have done the obvious cross check ( I tested the motor with direct power and its fine, up and down no issue ) this would have placed a full 12 volts from you external power supply / additional battery.
this is good news , but the volts actually reaching the motor are travelling thru the wiring loom and switches and maybe lower due to electrical resistance / poor earthing.

You may even find that unless the engine /alternator are running the volts delivered to the motor may not be enough to overcome the mechanical resistance to movement.
Servo motors and voltage stabilised version would be better but are too expensive for car manufactures, therefore Stepper motors are employed , these tend to be AMP hungry ( can place a load on the battery especially if stalled)
and while they have a lower initial torque capability. It follows that where Volts * Amp equal Watts that if less volts are available (especially the case in cold weather when you battery capacity is low )
then not enough power is available to unstick / unstall the motor , that may also be impeded by a wet / green moss felt seal on the window assembly .

In addition to these winter weather problems , another occurrence on Stepper motors is that the surface of the fixed armature (holding windings) become moist / rusty
and while the permanent magnets held in the housing also are hydroscopic and melting ice literally explodes them in wet-ice-warm cycle environment.

This leaves magnetic debris inside the housing, often a motor in this situation will first start to run slower and then may only be able to run in one direction (even jamming in reverse) It may still be serviceable
if you open the housing and clean away the rusty / broken particles.

Just some tips , it might not be any of the above.

Problem Sorted,

New switch fitted in rear window, but would only operate window down
New switch fitted on drivers side now both controls will operate the window up and down

Onto the next problem now !!