HORN INOPERATIVE LACK OF STEERING COLUMN GROUND

Model and Year: 1986-89 M1 VANS WITH NON-TILT STEERING AND AUTOMATIC TRANSMISSION

THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 89-279-8B, DATED DECEMBER 1989. THE LABOR TIME HAS BEEN CORRECTED. ALL COPIES OF 89-279-8B SHOULD BE DISCARDED.

An inoperative horn condition due to a lack of steering column ground may exist on some 1985-1989 M1 vans equipped with non-tilt steering columns and automatic transmissions.

IMPORTANT: The intermediate steering shaft is not the design intended ground path for the horn circuit and should not be replaced due to lack of steering column ground (inoperative horn).

Other causes MUST be checked first to verify that the problem is due to a lack of steering column ground and not a blown fuse, loose connection, open harness, failed switch, relay, etc. Consult the applicable 1985-1988 Light Duty Service Manual, Section 8B-Chassis Electrical or the 1989 Light Duty Service Manual, Section 8D-Chassis Electrical for diagnosis of the horn system.

Use the following procedures to diagnose and verify a lack of steering column ground:

1. Check for horn operation with the ignition key removed and the steering wheel locked. The horn should operate. If the horn does not operate, add a star washer, P/N 11503663, between the steering column mounting plate and bolt. There are four (4) mounting plate bolts, the star washer may be installed under any one of these to provide a ground path. Torque the screw 8 to 11 Nm or 6 to 8 Lbs/Ft (Figure 1).

2. Turn the ignition to the "on" position and check for continuity between the lower steering shaft and the steering column outer jacket (Figure 2).

IMPORTANT: DO NOT use the intermediate shaft for the continuity check.

3. If no continuity is found this confirms a lack of steering column ground. This condition may be caused by a broken, missing or burned horn circuit contact. The horn contact is located in the steering column housing (Figure 3).

NOTICE: DO NOT add a jumper wire across the intermediate steering shaft for an inoperative horn complaint.

DO NOT replace the intermediate steering shaft for an inoperative horn complaint.

Burned horn contacts can be caused by using the steering shaft or intermediate steering shaft as a ground; i.e. jump starting the vehicle, etc.

4. If the inoperative horn condition is caused by a broken, missing or burned horn contact, replace the contact, P/N 7832984, AND the bearing retaining bushing, P/N 7832808 (Figure 3). Refer to the applicable 1985-1988 Light Duty Service Manual, Section 3B4-Steering Column or the 1989 Light Duty Service Manual, Section 3F1-Steering Column-Standard for non-tilt steering column unit repair instructions.

Parts are currently available through GMSPO.

For vehicles under warranty use:

Labor Operation Number: E7320 - Replace Bearing Retaining Bushing and Horn Contact

Labor Time: 0.8 Hr.

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.