No power to windows.

I have a 1990 Buick Lesabre station wagon. Full size. I have a problem with power windows not working that also affected the passenger side power mirror & Radio. I got some help from AI with my question. I have no power to drivers side master control of all 4 windows. I checked circuit breaker. Good. All fuses are good. No power on Pink wire. Some where there is a short? Broken wire? Can't find the relay. The relay AI told me to check in dashboard above glove box. Found one relay. Disconnected or connected no change. One wire on relay I checked had less than 12 volts. another wire had 12 volts to relay. Some where between fuse box & master switches is a problem. So I cut the Pink wire just before the switch. Found a connector male. Ran wire from that connector on fuse box & ran a 12 gauge wire directly to Pink switch power. Windows worked. But power mirror & rear window still don't work. Any ideas. I replaced the OEM AM FM Radio. Kenwood AM FM CD player in place now. It works. I had a 1973 Buick Riviera till it was stolen 3 years ago. Had same problem. I found the power window relay & replaced it. Windows worked. That relay was above the kick panel under dash close to fuse box.

 

Often times, it's the ground connection causing trouble. Especially, if all of these devices share a common ground