97 sunroof will not close automatically

[mclan]

1997 Bonneville SSE with sunroof. Sunroof will not close automatically. Using open/close buttons, have to manuver to closed position.

Cannot locate any limit switches etc.

Any comments on how sunroof open/close system works?

Thanks

[lakerfan1784]

the sunroofs on the bonnevilles open automatically, and require you to hold the switch to close them. is it not powering closed?

[mclan]

Yes it is powering closed, but it is not automatically stoping at the closed position.

If the sunroof was in the slide back position, and you try to close it, the sunroof will automatically continue past the closed position, and open to the tilted up position.

Use to be if you held down the close button for a few seconds and released, sunroof would close automatically and "stop" in the closed position.

Currently I have to give the close button short taps until sunroof seems to be in closed position, exit car, and see if sunroof closed in correct position. Hard to tell from inside of car.

Seems like there would be limit switches (or some type of position sensing device) to remove power once sunroof is in closed position.

Sunroof has power in all directions, is just no automatically finding closed positions from either direction of travel.

Thanks for response.

[Jed Rule]

The sunroof motor needs to be syncronized with the module.
This is the process according to my 1995 service manual.
Check if your car is the same:
Ensure roof is in the closed position. Remove 3 screws securing motor to track and roof panel. Release gear syncronizing lever from notch on motor casting and rotate lever in direction of arrow on motor casting. The cams should turn freely when lever is released. If the cams do not turn freely, be sure the lever is rotated fully upward. Using 4mm hex wrench rotate the small cam untill aligning mark (hole in large cam) is aligned with centerline drawn thru the shafts of the large and small cams. Return syncronizing lever to notched position.

It sounds simple enough, but this is going to require you to partially lower the headlining in the front. You might want to take it to a sunroof specialist.