The PWM control in the G7 Honda is a 200Hz PWM square wave running at 10v Peak.

Dash-light control full brightness: PWM stops and Line drops to 0 volts.

Dash-light control 90% brightness: PWM around 10% on 90% off

Dash-light control 50% brightness: PWM 50% (1:1) or 50% on 50% off

Dash-light control fully dimmed: PWM around 90% on 10% off

The PWM drive line may be limited in its current sink capacity, therefore if you want to control the brightness of other lights with this signal, it would be advisable to interface this line via a small two transistor circuit.

See LCD Back Light control for more info.

Pin  A9 = 12 volt when Lights are on.
Pin A19 = PWM signal.
Pin A20 = Ground.
A1: 12v when radio is ON - external AMP control.

A3:   Radio/CD Steering Wheel buttons input.

A11: Radio/CD Steering Wheel buttons ground.

A2:  12v ACC, Main radio power from IGN switch.

A9:   LEDS On = 12 volts from Light switch.

A10: Constant 12 volts for radio backup.

A19: PWM signal from Dash light control.

A20: Ground.