I do not think there is a limit Switch in any of the Window Motors. Somewhere there is a thread showing a Moter taken apart for re-lubing.

It could be that the Window Relay somehow acts as the limit switch. As far as I can Remember I have not read a thread or post of anyone replacing the Window Relay.

Ounce the Door Panel is off locate the Window Motor wires and test them on a Batery (you will nee Jumper Wires) directly to a Battery.
If they work fine and there is no Regulator issues it is look else where for the cause of the problem.

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84 300D, 82 Volvo 244Gl Diesel