GM Service Manual Online
For 1990-2009 cars only

Range Signal

A

B

C

Park/Neutral

HI

LOW

HI

Reverse

LOW

LOW

HI

Park/Neutral

HI

LOW

HI

D4

HI

LOW

LOW

D3

HI

HI

LOW

D2

HI

HI

HI

D1

LOW

HI

HI

Illegal

LOW

HI

LOW

Illegal

LOW

LOW

LOW

LOW = 0 volts

HI = Ignition voltage