Can anyone tell me the symptoms of a bad k40? My windows just stopped working (fuse ok). When i activate the pw button, i hear a quick clicking coming from the k40 box.

 

I don't think the Relay Control Module has anything to do with the windows.
One way to test is to turn your key to the on position (just before starting). Then let it stay on for about 45 seconds and see if your engine fan goes to a high speed.

 

The windows are operated by the BCM (Body Control Module). Power to the BCM comes thru the RCM (Relay Control Module) but it is not likely the RCM is causing this fault. Over the last few years, the BCM has gone from being the one module that almost NEVER fails, to a module we are now seeing fail a few times a year (on our Crossfire Facebook pages).

IF you are trying to move the windows with the engine off, start the engine and raise the tack to 2000. Now try the windows, if they now work, you have a low system voltage problem. In this case, look for a weak battery, corroded cables, etc.