See Figures 1, 2, 3 and 4
The steering box (manual or power) consists of recirculating balls, which transmits force from the worm gear to the sector gear. A relay type steering linkage is used with a pitman arm connected to one end of the relay rod. The relay rod is supported by 2 idler arms; the idler arms pivot on a support which is attached to the frame. The relay rod is connected to the steering arms by 2 adjustable tie rods. Most models are equipped with a steering column which is designed to collapse on impact, thereby reducing possible chest injuries during accidents. When making any repairs to the steering column or steering wheel, excessive pressure or force capable of collapsing the column must be avoided. The ignition lock, ignition switch and an anti-theft system are built into each column.
Late-model vehicles are equipped with a driver's side Supplemental Inflatable Restraint (SIR) or Air Bag system. On these models it is EXTREMELY IMPORTANT that you follow correct servicing procedures in order to prevent serious personal injury that could result from an accidental deployment, or worse that could result if a repair prevents the system from operating properly. The air bag system should be properly disarmed BEFORE ANY PROCEDURE ON OR NEAR THE STEERING COLUMN. Also, after repairs are performed, the system should be properly armed and the system trouble indicator light should go out, indicating proper system operation. IF THE LIGHT REMAINS ON, HAVE THE VEHICLE TOWED TO A REPUTABLE REPAIR FACILITY.
The same basic style steering column is used on all 1985-95 Astro and Safari vans, with the possible option of standard or tilt wheel. This style of steering column has been used in GM vehicles for many years. It mounts a few of the switches (turn signal, wiper/washer and the ignition lock cylinder) inside the column, making a partial disassembly necessary for their replacement). The column mounts a few other items (ignition and dimmer switches) on top of the column, making it necessary to at least lower the column assembly from the dash for access. In 1996 an interior redesign allowed a change in column to a more simplified unit which mounts most switches in a more easily accessible position (under the upper and lower column shrouds).