Motor, Sunroof: Operation

The power sunroof servo motor is completely controlled by the circuitry of the on-board electronic module. The module receives battery current on a fused B(+) circuit from a fuse in the Power Distribution Center (PDC) in the engine compartment and has a path to ground at all times through a take out and eyelet terminal connector secured by a ground screw to the body sheet metal. These connections allow the module to function regardless of the ignition switch position.

However, the module also monitors an input on a fused ignition switch output (run) circuit and a vehicle speed signal input from the Body Control Module (BCM) and responds to inputs from the sunroof switch only when the ignition switch is in the ON position. The module then monitors a separate input circuit for each switch position, which it uses to determine the proper outputs to the power sunroof motor. A positive and negative battery connection to the two motor brushes will cause the power sunroof motor to rotate in one direction. Reversing the current through these same two brushes will cause the motor to rotate in the opposite direction.

The hard wired circuits of the power sunroof motor as well as those between the electronic module and the switch in the headliner may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the electronic module integral to the power sunroof motor. If the power sunroof switch and the hard wired circuitry test okay but the motor, the express features or the Excess Force Limitation (EFL) feature are still ineffective following the initialization procedure, the motor and module must be replaced as a unit.