WASHINGTON - Federal safety officials have stepped up their investigation of complaints that the steering wheels of some General Motors trucks unexpectedly jerk or twitch in turns or at highway speeds.
The investigation covers 1997-99 Chevrolet and GMC full-sized C/K pickups and sport-utilities, including the Suburban, Tahoe and Yukon. About 2 million of the vehicles are on the road.
The National Highway Traffic Safety Administration and the company have recorded 76 complaints about erratic steering. One complainant said an attempted single lane change caused the truck to cross three traffic lanes. The agency said it has not yet confirmed four reports of crashes.
GM notified NHTSA that 42,000 of the trucks have had warranty repairs on components of the variable steering assist system. GM spokesman Greg Martin said the warranty repairs are not necessarily related to the steering complaints NHTSA is investigating.
The agency, upgrading its defect investigation from a preliminary evaluation to an engineering analysis, said it believes a fault in a steering wheel speed sensor sends false signals to the variable assist control electronics, causing unanticipated steering wheel movements.
The electronics alter the size of an opening, allowing more or less hydraulic fluid to move through the system, Martin explained.
In a new defect investigation, NHTSA said it is looking into 21 complaints of excessive heat, smoke or fire in the area of the ignition switch on 1994-96 Dodge Ram trucks.
The agency said the symptoms may be related to current draw that is above switch capacity, especially when many accessories are operating, and may be accompanied by stalling and illumination of warning lights. About 690,000 of the vehicles are on the road.
NHTSA said it opened another investigation after receiving two complaints of inadvertent airbag deployments in 1998 Oldsmobile Cutlasses. About 50,000 cars are affected.
NHTSA said it closed its investigation of inadvertent airbag deployments in some DaimlerChrysler minivans after the company decided to recall nearly 1 million of its 1994-95 Dodge Caravan and Grand Caravan, Plymouth Voyager and Grand Voyager and Chrysler Town & Country vehicles.
Before the announcement, NHTSA said it and the company had collected 53 complaints about airbags deploying without crashes; the agency said the deployments injured 21 people and led to two crashes.
NHTSA closed several other cases after manufacturers agreed to recalls. They included investigations of the following complaints:
Inadvertent side airbag deployments on 1999 BMW 3-series cars.
Headlight switch failures on 1996 Ford Contours and Mercury Mystiques.
Ruptures of hydraulic clutch lines on 1996-97 Dodge Ram trucks.
Underhood fires on 1992-93 Lincoln Town Cars.
The agency closed an investigation of complaints about shift-lock mechanisms on 1997 Ford E-250 vans after finding insufficient evidence of a defect.
Other new defect investigations announced by NHTSA:
1997-98 DODGE STRATUS, PLYMOUTH BREEZE, CHRYSLER CIRRUS AND SEBRING
Problem: Carpeting or floor mats entangle in exposed steering shaft and impede steering function.
Vehicle population: 570,000.
1998 FORD MUSTANG COBRA
Problem: Smoke and/or fire emanates from center console area.
Vehicle population: 8,400.
1998 KIA SEPHIA AND SPORTAGE
Problem: Windshield wiper fails when arm separates from pivot.
Complaints: Three, involving eight incidents.
Vehicle population: To be determined.
1995 MAZDA PROTEGE
Problem: Headlights stop working, especially with turn signals on.
Vehicle population: 77,000.
1993 VOLKSWAGEN PASSAT
Problem: Fog lamps catch fire.
Vehicle population: 13,000.
1992 FORD AEROSTAR
Problem: Right front brake hose ruptures at connection to metal line.
Complaints: Seven, including two crashes.
Vehicle population: 150,000.