I'm sure it's the motor - it's got juice, it clicks, it just won't do anything. And also now sure that the motor does not come out without the regulator. There's no room at all to take the bolts out - less than 1/8 inch between the regulator and the inner door panel - at least on a 124 body. This seemingly leaves only one solution - turn the motor somehow to lower the glass, so that the regulator/motor can be removed.