TAP Shift Switches
The TAP Shift system allows the driver to manually shift gears by using the TAP Shift switches located on the steering wheel. The TAP Shift system is activated when the gear selector is placed in the manual, M, position and is deactivated in all other positions.
The Left TAP Shift switch is a 3 position momentary switch that contains a series of 3 resistors. Each position of the TAP Shift switch will apply ignition voltage to 1 or more resistors depending on the switch position. In the static position, ignition voltage is applied to an 8.25K Ω resistor. When the Left TAP Shift switch is pushed, requesting an upshift, ignition voltage is also applied to a 4.42K Ω resistor wired in parallel to the 8.25K Ω resistor. When the Left TAP Shift switch is pulled, requesting a downshift, ignition voltage is applied to a 1.5K Ω resistor also wired in parallel with the 8.25K Ω resistor. This combination of resistors allows ignition voltage to be reduced by a given amount. The Powertrain Control Module (PCM) measures the drop in ignition voltage at the Remote Shift Selector input and that amount of voltage drop is used to determine if there is a request for an upshift, downshift or no request.
The Right TAP Shift switch is a 3 position momentary switch that is wired in parallel with the Left TAP Shift switch. In the static position, the Right TAP Shift switch is open. Pushing the Right TAP Shift switch will apply ignition voltage to the 4.42K Ω resistor of the Left TAP Shift switch, requesting an upshift. Pulling the Right TAP Shift switch will apply ignition voltage to the 1.5K Ω resistor of the Left TAP Shift switch, requesting a downshift.