NHTSA said about 12 million vehicles have been part of the recall and nearly 5 million still have not been fixed. A similar warning was issued in February but officials said the rate of the vehicles being repaired has declined.
The recalls have affected Ford's popular F-Series pickup trucks and led to hundreds of complaints and dozens of lawsuits over engine fires.
Ford spokesman Wes Sherwood said the Dearborn, Mich., company supported the effort to communicate with owners. He said owners have received several recall notices but "the return rate has been lower than expected or hoped (for)."
Dealers have installed a fused wiring harness into the speed control electrical system as part of the recall, and the government said replacement parts are available. Owners can take their vehicle to a dealer to have the cruise control deactivated until the parts arrive.
2000-2003 Excursion (built prior to 11/4/02)
1992-2003 Econoline E-150/250/350
1996-2003 Econoline E450
2002-2003 Econoline E550
2001-2002 Explorer Sport (2 door) & Sport Trac
2003-2004 F-150 Lightning
1993-2003 F-Series (Under 8500 lb. GVW)
1993-2003 F-Series (over 8500 lb. GVW) - all plants except Cuautitlan
1994-2003 F-Series (over 8500 lb. GVW) - Cuautitlan built only prior to 1/7/03
1995-2002 F-53 Motorhome
1992-1998 Town Car
1992-1998 Crown Victoria
1992-1998 Grand Marquis
1993-1998 Mark VIII
1993-1995 Taurus SHO (automatic transmission)
*equipped with speed control. Diesel engine equipped vehicles are excluded from recall