Seats - Power Buick Century V

Description

Power seats operate using toggle switches located on seat side or in 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 fuse panel and protects power seat wiring.

6-WAY POWER SEATS

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

In 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 one controls horizontal movement. Motor then moves the seat. Releasing switch disengages drive motor from cables.

POWER RECLINING SEAT BACK

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

SPORT LUMBAR SEATS

Sport lumbar seat is an option on some models. (Scheme 1) It is used on either the driver's seat only, or on both front seats. Power is supplied by a 30-amp circuit breaker in fuse block. Adjustments are made by a solenoid valve assembly located under seat(s). Operation is controlled by a switch located on seat side, or in center console.

Backrest lateral restraints (side bolsters) are power adjusted 15 degrees in or out. Lumbar support can be pneumatically adjusted from soft to firm by inflating the 3 compartment bladders located in seat back. Inflation of bladders is controlled by a pressure pump, bleed down valves and a control switch. Seat back angle is power adjusted by a control in left bolster.

Scheme 1

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 attaching screws. (Scheme 2)
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 2

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. Reconnect previously disconnected front and rear vertical drive cables. Seat should be in phase. If not, repeat procedure.

REMOVAL & INSTALLATION

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

1. Remove seat. See «BASIC SEAT ASSEMBLY»(/buick/century/v-1982-1996/remont/seats/#seats-power). Place seat upside-down on a clean bench. Disconnect drive cables at adjuster being removed. (Scheme 3) Squeeze oblong connector to remove. On bucket seats, remove motor support-to-adjuster bolt.
2. Remove adjuster-to-seat bottom bolts and remove seat adjuster. Note locations of spacers (if equipped). To install, reverse removal procedure and ensure seats are in phase. See «SEAT ADJUSTER PHASING»(/buick/century/v-1982-1996/remont/seats/#seats-power__seat-adjuster-phasing) under ADJUSTMENTS.

Scheme 3

Remove seat. See BASIC SEAT ASSEMBLY . Place seat 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. See «BASIC SEAT ASSEMBLY»(/buick/century/v-1982-1996/remont/seats/#seats-power) . Place seat 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. See «SEAT ADJUSTER PHASING»(/buick/century/v-1982-1996/remont/seats/#seats-power__seat-adjuster-phasing) under ADJUSTMENTS.

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

1. Disconnect battery ground cable. Remove seat cushion and release bail clip from frame panel. Disconnect pneumatic tubing and electrical connector to lumbar control assembly. Remove hog ring at underside of seat to gain access.
2. Remove face plate and remove control assembly through bottom of seat cushion. If necessary, valve body can also be replaced at this time. To install, reverse removal procedure.

1. Disconnect battery ground cable. Remove seat cushion. Remove 4 cushion frame panel-to-adjuster bolts. Disconnect electrical connector and remove seat from vehicle.
2. Disconnect electrical and pneumatic harness connectors at motor. Remove motor and pump assembly-to-frame parts. Remove motor from seat cushion frame. To install, reverse removal procedure. Check operation of motor and pump.

No Seat Functions Operate

1. Disconnect seat switch connector. Connect a test light between terminal "F" and ground. If test light glows, go to next step. If test light does not glow, repair open in circuit No. 60.
2. Connect test light between seat switch connector terminals "C" and "F". If test light does not glow, repair open in circuit No. 151 or 152. If test light glows, ensure switch is mated correctly. If okay, replace seat switch.

Some, But Not All Seat Functions Operate

1. Disconnect seat switch connector. Connect a test light between terminals "C" and "D". Operate rear height switch in up and down positions. If test light glows, go to next step. If test light does not glow, replace seat switch.
2. Connect test light between seat switch connector terminals "A" and "B". Operate front height switch in up and down positions. If test light glows, go to next step. If test light does not glow, replace seat switch.
3. Connect test light between switch terminals "E" and "F". Operate front height switch in up and down positions. If test light does not glow, replace seat switch. If test light glows, check wiring to motors. If wiring is okay, replace inoperable motor(s).

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 horizontal actuator-to-rack gear adjusted too tight. See «HORIZONTAL ACTUATOR»(/buick/century/v-1982-1996/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 gearnut 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 gearnut tension spring. To correct looseness, grind top of vertical gearnut 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 gearnut. 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 gearnut. 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 motor fields and control switch. Check for a defective field coil.

Power Seats Wiring Diagram. Scheme 4

Power Reclining Seats Wiring Diagram. Scheme 5

See also:
• COMPUTER RELEARN PROCEDURES
• BASIC SEAT ASSEMBLY
• SEAT ADJUSTER PHASING
• HORIZONTAL ACTUATOR