GM Service Manual Online
For 1990-2009 cars only

Range Signal

A

B

C

Park

HI

LOW

HI

Reverse

LOW

LOW

HI

Neutral

HI

LOW

HI

D4

HI

LOW

LOW

D3

HI

HI

LOW

D2

HI

HI

HI

D1

LOW

HI

HI

Invalid

LOW

HI

LOW

Invalid

LOW

LOW

LOW

LOW = 0 volts

HI = Ignition voltage