Installation guide

Here is a test: Cut the wire which pulses (+)12V on lock, and then operate the switch to unlock.

■ If all doors unlock, the vehicle uses Type A system.

■ If you lose all door lock operation in both directions, you are operating the master switch in a Type C system.

■ If you lose all door lock operation of one or more doors, but not all motors stop operating, and other doors

still work, you have cut a wire leading directly to one or more motors. You must instead find the actual wires

leading to the switch.

Many domestically-made GM vehicles use Type A locks. However, many more GM vehicles are Type C than in pre-

vious years. The full-size pickups (1989-up), many of the S10 Blazers, the Corvette, 1995 Cavalier/Sunfire 1993

and newer, Camaro/Firebird all use Type C door locks, and cannot be controlled without a 451M! Almost all

domestically-built Fords are Type C. Ford builds almost no Type A systems. Chrysler builds both Type A and Type

C, so care must be taken in determining the type of door locking system.

IMPORTANT! Remember that the functions of these wires are reversed between Type A and Type B!