Type A: Positive-Triggered, Relay-Driven System - Avital 3300L Installation Manual

type A: positive-triggered, relay-driven system

The system can control Type A door locks directly, with no additional parts. The switch will have three wires on
it, and one will test (+)12V constantly. The others will alternately pulse (+)12V when the switch is pressed to
the lock or unlock position.
If you cannot get to the switch, and you find a set of wires that pulse (+)12V alternately on lock and unlock,
make sure that it is not a Type C direct-wire system.
Here is a test: Cut the wire that pulses (+)12V on lock, and then operate the switch to unlock.
■ If all doors unlock, the vehicle uses a 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, but not all motors, and other doors still work, you have
cut a wire leading directly to one or more motors You must reconnect the wire and search again for 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 Blazers, the Corvette, '95 Cavalier/Sunfire 1993 and the
newer, Camero/Firebird all use Type C door locks, and cannot be controlled without a 451M. Almost all domesti-
cally-built Fords are Type C. Ford builds no type A systems. Chrysler builds both Type A and Type C, so proceed
with caution.
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