On a 1995 disco the rear windows will only work after the ignition has been on for 10 minutes. I couldn't find the relay. Any ideas?

 

on the passenger side there is a "window control unit" behind the glove box area inside you will find a black incased ecu about 6 inches from the right side inner steel panel its called a window control relay. Pull the plug and with a small pocket flat blade screw driver seperate the cover from the ecu hardware inside then look at all the soider connections beneath the circuit board directly beneath the relays on the board take an iron and touch each one. It will fix this, the soider seperates from the pin

 

I fixed my windows! It was exactly what you said. It was a plastic black box behind the glove compartment (which needed to be removed with a few other things) and I opened the box and took out the circuit card. I found 3 bad solder joints. I resoldered the joints with a U-techtic 90/10 solder so that it doesn't happen again. Thanx for the help, Rovercountry.

 

This was also the problem with mine...I just now fixed it.
1 bad point on the circuit board caused both rear windows to not work.