Before replacing the relay,
check for supply voltage at the relay seats.
If no voltage check the fuse(s), making sure they have seated correctly. They like to corrode causing strange little problems like you describe.
If voltage is present check for supply voltage from the switch
if yes jumper the relay block pins
if no change the switch or find out why no power is coming from that circut
if the windows move when jumpered change the relay
if they dont
check for voltage at the motor
if no check wiring from relay to motor
if yes change the motor

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1983 Mercedes 300SD
1987 Mercedes 300SDL
2001 VW Passat 2.8 AWD
2007 OM642 Jeep WK 4x4