My 1999 DSDP, has the drivers door and the power window has no relay.
The switch reverses power to the motor.
You problem sounds like , internal issues in the motor , or binding in the track.
Youíre going to have to access the motor for further testing.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.