TOP PULLDOWN MOTOR CYCLES CONT (DIAG./REPLACE PULLDOWN MOTOR)

SUBJECT: TOP PULLDOWN MOTOR CYCLES CONTINUOUSLY

MODELS AFFECTED: 1987 -1993 ALLANTES

This bulletin supersedes Service bulletin T-92-55, Group 10, which should be discarded. This bulletin is being revised to update information in Section II, add a model year, and add part numbers.

Some 1987-1993 Allantes may experience a condition where the top pulldown unit cycles up and down continuously after unlatching or latching the rear bow. This condition is caused by an unwanted ground being supplied to the pulldown unit or a misadjusted soft top hook position switch.

I. PULLDOWN UNIT CYCLES AFTER UNLATCHING THE SOFT TOP ----------------------------------------------------- If the condition occurs after unlatching the rear of the top, an unwanted ground is being supplied to the motor. Typically, the unwanted ground is caused by a chafed or pinched wiring harness at the pulldown unit or a chafed or pinched main release cable near the left rear speaker housing. To repair this condition use the following service procedure:

1. Remove the pulldown unit from the stowage well, and inspect the wiring harness conduit in the immediate vicinity for cuts, chafing, or pinch marks. Be sure to check the portion of the harness which runs up to the pulldown unit jaws. If suspect, open the conduit and inspect for wire damage. Repair wiring as needed.

2. If the wiring harness appears okay, disconnect all wiring connections at the pulldown unit (one motor connection and the wire screwed to the jaws). Check for a short to ground on circuit #739 on 1990-1993 models or #897 on 1987-1989 models. Refer to Section 8A, Cell 121-0 for circuit details. Repair short as necessary.

3. If the wiring checks okay, inspect the main release cable housing for chafing or cuts that allow the metal cable inside to contact a grounded surface. Especially check the cable assembly where it passes behind the left rear speaker housing and near the shoulder belt retractor on its way to the release handle behind the driver's seat. If grounded, repair or replace the cable as necessary using cable P/N 1640708 and sleeve P/N 1640707).

4. If the main release cable appears okay, replace the pulldown unit (use P/N 3526879 for 1987-1992 models, P/N 3537915 for 1993 models) for an internal short.

For warranty purposes use Labor Operation T6606 at .6 hour plus diagnosis time of 0-.3 hour depending on actual time used.

II. PULLDOWN UNIT CYCLES AFTER LATCHING THE SOFT TOP ---------------------------------------------------- If the pulldown unit cycles continuously after the soft top is latched in the rear, the metal extension arm on the soft to hook position switch is out of adjustment. Refer to Figure 1. To repair this condition use the following service procedure:

1. Unlatch the rear of the soft top and open the stowage cover. Verify the metal extension arm on the hook position switch (refer to Figure 1 )is free to move and not physically distorted or damaged. If distorted or damaged, repair or replace as necessary. Proceed to next step.

NOTE: A distorted or damaged extension arm indicates excessive force has been used in latching the rear bow. To prevent recurrence, ensure that the soft top hook and pulldown unit jaws are properly aligned and operating correctly. Check the main and emergency release cables (refer to Figure 1) for binding/misadjustment which may hold the jaws slightly open and not able to full grasp the hook. Make sure the hook does not contact the pulldown unit when raising or lowering the soft top. Also make sure the customer understands the correct procedure for raising the top before returning the vehicle.

2. Cycle the pulldown unit downward using the rocker switch behind the driver seat. As the unit is traveling downward, manually depress the extension arm on the hook position switch and verify the pulldown unit stops when it reaches the bottom of its travel. If the unit does not stop, replace the pulldown unit for an internal short (using P/N 3526879 for 1987-1992 models and P/N 3537915 for 1993 models). Proceed to next step.

3. With the stowage cover in the raised position and the pulldown unit at the top of its travel, lower and latch the soft top rear bow into the pulldown unit. From inside the car observe pulldown unit operation and check how the soft top hook contacts the metal extension arm on the hook position switch. The bottom of the hook should overlap and solidly contact the top surface of the metal extension arm. If the hook passes in front of or slips off of the extension arm, release the hook and reform the extension arm slightly forward and recheck contact. Proceed to next step when proper contact is achieved.

4. If the pulldown unit continues to cycle but hook to metal extension arm contact is good, reform the metal extension arm slightly upward and try latching the top again. Repeat the reforming operation as necessary until the pulldown unit will stop at the bottom of its travel.

Parts are currently available from GMSPO.

Part Number 3537915 is expected to be available on February 8, 1993.

For warranty purposes use Labor Operations T6606 at .6 hour for pulldown replacement and T6607 at .2 hour for hook position switch adjustment.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.