Seats - Power Buick Roadmaster VIII

DESCRIPTION

Power seats operate using toggle switches located on seat side or in the door arm rest. Seat adjusters are powered by a 12-volt reversible motor with an internal circuit breaker. A 30-amp, plug-in circuit breaker is located in the fuse panel and protects the power seat wiring.

6-WAY POWER SEATS

Two types of power seats are used. One type has 3 reversible motors that operate the seat functions. Front and back parts of the seat are operated by different motors and can be raised and lowered independently. The third motor controls forward/backward movement. Drive cables connect motor to gear nuts, which turn jack screws and adjusters at each side of seat.

In the second type, each seat uses a single motor with 3 solenoids, 6 drive cables and a transmission. One solenoid controls front vertical movement, one controls rear vertical movement and the other controls horizontal movement. The motor then moves the seat. Releasing the switch disengages the drive motor from the cables.

POWER RECLINING SEAT BACK

Power reclining seat back is an option on some models. The system includes a motor under the seat, drive cable, actuator and control switch. The switch is on the seat edge or the armrest. Power seat back recliners operate independently of other power seat adjustments.

HORIZONTAL ACTUATOR

1. Chucking can be corrected by adjusting horizontal actuator and pinion gear to fully mesh with lower adjuster track rack gear. Operate seat to full up position and about 3/4 forward. Loosen horizontal actuator screws.
2. Using a large screwdriver, apply outward pressure on horizontal actuator (about 15-25 ft. lbs.) and energize horizontal switch to move seat slightly fore and aft. This keeps seat horizontal actuator pinion gear teeth in close contact with lower track rack gear teeth and eliminates free play between gear teeth. Tighten screws while maintaining outward pressure against horizontal actuators.

Scheme 1

SEAT ADJUSTER PHASING

When installing power seat adjusters (except at back recliner), ensure each pair of adjusters is in phase with each other. When adjusters are out of phase, one adjuster will reach its maximum travel limit before the other, resulting in improper seat travel.

Horizontal Travel

Operate seat until one adjuster reaches full forward position. Detach horizontal drive cable from adjuster which has reached its travel limit. Operate seat forward until other adjuster reaches its full forward position. Reconnect drive cable of first adjuster. Adjusters are now in phase.

Vertical Travel (Front Or Rear)

1. Operate seat until one adjuster has reached fully raised position at both front and rear vertical travel limits. Disconnect both front and rear vertical drive cables from adjuster which has reached its travel limit.
2. Operate seat until other adjuster reaches fully raised position. Now reconnect previously disconnected front and rear vertical drive cables. Seat should now be in phase. If not, repeat procedure.

Jerky Horizontal Operation

1. Check for improper lubrication of adjuster shoes and channels. To correct operation, lubricate adjuster upper channel and adjuster shoes.
2. Check for adjuster horizontal actuator gear too tight to rack gear. See «HORIZONTAL ACTUATOR»(/buick/roadmaster/viii-1991-1996/remont/seats/#seats-power__horizontal-actuator) under ADJUSTMENTS.

Horizontal Chuck Or Looseness

Check for horizontal actuator improperly adjusted. See HORIZONTAL ACTUATOR under ADJUSTMENTS.

One Adjuster Will Not Operate Horizontally

1. Check for disconnected or damaged horizontal drive cable. To correct operation, check horizontal drive cables and replace if damaged.
2. Check for inoperative horizontal actuator. To correct operation,replace horizontal actuator assembly.

One Adjuster Will Not Operate Vertically

1. Check for disconnected or damaged vertical drive cable. To correct operation, check vertical drive cables and replace if damaged.
2. Vertical gear nut inoperative. To correct operation, replace vertical actuator assembly.

Both Adjusters Will Not Operate Horizontally &/Or Vertically

Check for inoperative horizontal and/or vertical solenoid in transmission. Check for damaged, broken or inoperable solenoid plunger, shaft, gear or drive gear. To correct operation, replace damaged or defective parts.

Vertical Chuck Or Looseness

Check for excessive clearance at vertical gear nut tension spring. To correct looseness, grind top of vertical gear nut shoulder until slack is removed.

Power Seat Back Motor Operates, But Seat Back Does Not Move

Check for disconnected or broken drive cable. Check for damaged or broken reclining actuator gear nut. Ensure reclining actuator is not disconnected from arm of seat back lock or support. Check for incorrect application of seat back lock or support.

Power Seat Back Operation Jerky

Check for kink or damage to drive cable. Check for bind in reclining hinge arm. Check for damaged or bent jack screw. Check for damaged actuator gear nut. Ensure there is sufficient lubrication. Check for loose jack screw lock nut.

Inoperative Adjuster Motor

Check for shorted or open circuit between power source, switch or motor. Check for a defective adjuster motor.

Motor Operates But Adjuster Will Not Operate

Check for a shorted or open circuit between switch and solenoid. Check solenoid for defects.

Motor Operates, But Adjusters Or Recliner Only Operates In One Direction

Check for a shorted or open circuit between one of the motor fields and control switch. Check for a defective field coil.

Flow Chart 1, All Positions Do Not Operate (All Models). Scheme 2

Flow Chart 2, Entire Seat Will Not Move Forward &/Or Back (All Models). Scheme 3

Flow Chart 3, Front Height Will Not Move Up &/Or Down (All Models). Scheme 4

Flow Chart 4, Rear Height Will Not Move Up &/Or Down (All Models). Scheme 5

Roadmaster Chart 1A, LH Recliner Inoperative (W/Lumbar) RH Recliner Operates Normally. Scheme 6

Roadmaster Chart 2A, RH Recliner Inoperative (W/Lumbar) LH Recliner Operates Normally. Scheme 7

Roadmaster Chart 3A, RH Recliner Inoperative (Without Lumbar). Scheme 8

Roadmaster Chart 1B, All Lumbar Supports Inoperative. Scheme 9

Roadmaster Chart 2B, All Lumbar Supports: Inflate Mode Inoperative, Deflate Operates Normally. Scheme 10

Roadmaster Chart 3B, All Lumbar Supports: Deflate Mode Inoperative, Inflate Operates Normally. Scheme 11

FLOW CHART 4B, UPPER LUMBAR SUPPORT INOPERATIVE MIDDLE & LOWER SUPPORTS OPERATE NORMALLY (ROADMASTER)

Roadmaster Chart 4B, Upper Lumbar Support Inoperative Middle & Lower Supports Operate Normally. Scheme 12

FLOW CHART 5B, MIDDLE LUMBAR SUPPORT INOPERATIVE UPPER & LOWER SUPPORTS OPERATE NORMALLY (ROADMASTER)

Roadmaster Chart 5B, Middle Lumbar Support Inoperative Upper & Lower Supports Operate Normally. Scheme 13

FLOW CHART 6B, LOWER LUMBAR SUPPORT INOPERATIVE UPPER & MIDDLE SUPPORTS OPERATE NORMALLY (ROADMASTER)

Roadmaster Chart 6B, Lower Lumbar Support Inoperative Upper & Middle Supports Operate Normally. Scheme 14

Roadmaster Chart 7B, Upper Support Deflate Mode Inoperative Inflate Operates Normally. Scheme 15

Roadmaster Chart 8B, Upper Support Inflate Mode Inoperative Deflate Operates Normally. Scheme 16

Roadmaster Chart 9B, Middle Support Deflate Mode Inoperative Inflate Operates Normally. Scheme 17

Roadmaster Chart 10B, Middle Support Inflate Mode Inoperative Deflate Operates Normally. Scheme 18

Roadmaster Chart 11B, Lower Support Deflate Mode Inoperative Inflate Operates Normally. Scheme 19

Roadmaster Chart 12B, Lower Support Inflate Mode Inoperative Deflate Operates Normally. Scheme 20

REMOVAL & INSTALLATION

1. Remove seatbelt-to-floor anchor plate attaching bolts. Where required, remove door sill plates and turn back carpet to gain access to adjuster-to-floor attaching bolts. Operate seat to full forward and upward position. At rear of adjusters, remove adjuster-to-floor rear attaching bolts.
2. Operate seat to full rearward and full rear tilt position. Remove front adjuster-to-floor pan attaching nuts. Disconnect electrical connector under seat and remove seat. To install, reverse removal procedure.

SEAT ADJUSTER ASSEMBLY

1. Remove seat as previously described. Place seat upside-down on a clean bench. Disconnect drive cables at adjuster being removed. Squeeze oblong connector to remove. On bucket seats, remove motor support-to-adjuster bolt.
2. Remove adjuster-to-seat bottom attaching bolts and remove seat adjuster. Note locations of spacers (if equipped). To install, reverse removal procedure and ensure seats are in phase.

Scheme 21

Remove seat and place upside-down on clean bench. Remove trim on outside of seat for access to actuator. Unscrew reclining back drive cable from reclining actuator and detach cable from actuator. Remove pin securing reclining actuator coupling-to-hinge arm. Remove actuator. To install, reverse removal procedure.

1. Remove seat and place upside-down on clean bench. Disconnect wiring. On single motor seats, remove transmission-to-support screws and cable ends plates on transmission ends. Separate motor and transmission and disengage rubber coupling.
2. On 3-motor seats, remove motor support-to-motor mounting bracket screw. Disconnect drive cables from adjusters, remove nut from motor retaining rod and remove motor. To install, reverse removal procedure and check phasing

Disconnect battery ground cable. Remove seat cushion. Remove 2 screws retaining left side control panel trim plate. Pull face plate with switches attached out of armrest to gain access to electrical connector. Remove defective switch. To install, reverse removal procedure.

Scheme 22

Scheme 23

See also:
• COMPUTER RELEARN PROCEDURES
• HORIZONTAL ACTUATOR