Description

Cruise Control Description
The cruise control is selected from a switch located on the fascia. The cruise control operation is governed by a cruise control ECU located on the RH 'A' post behind the trim panel. Operation is controlled from two switches located on the steering wheel, a set/accelerate switch (SET+) and a resume/suspend switch (RES.).

A speed signal is supplied from the SLABS ECU to the cruise control ECU the cruise control ECU monitors the signal for use in its control logic circuits The cruise control system ECU supplies outputs to operate a vacuum pump and its internal control/dump valves

The vacuum acting within a pneumatic throttle actuator moves the actuator to the required position

Cruise suspend/resume - manual gearbox
Inputs to the cruise control ECU from a switch on the brake pedal mechanism or the clutch pedal mechanism can disengage the cruise control by interrupting a feed into the cruise control ECU The feed is used by the ECU to power the cruise control pump When the feed is interrupted the ECU logic circuits stop the operation of the cruise control pump open an internal dump valve and close an internal control valve. This action stops the actuator and suspends the cruise control function

In addition to the feed removal to the ECU when the brake pedal is pressed, a low voltage 'brakelight' signal is also sent via the Body Control Unit (BCU) to the cruise control ECU. The brakelight signal is also used by the logic circuits in the cruise control ECU to control the operation of the throttle actuator and control valves when the brake pedal has been pressed

Operation of the resume/suspend switch after a braking event, can restore the operation of the cruise control system if the vehicles speed is acceptable to the cruise control ECU

Cruise suspend/resume - automatic gearbox
A gearbox selector lever position sensor sends an input via the BCU to the cruise control ECU if the selector lever is in park neutral or reverse. An input to the cruise control ECU from a switch on the brake pedal mechanism will also disengage the cruise control by interrupting a feed to the cruise control ECU. The feed is used by the ECU to power the cruise control pump When the feed is interrupted the ECU logic circuits stop the operation of the cruise control pump open an internal dump valve and close an internal control valve. This action stops the throttle actuator and suspends the cruise control function.

In addition to the feed removal to the ECU when the brake pedal is pressed, a low voltage brakelight signal is also sent via the BCU to the cruise control ECU. The brakelight signal is also used by the logic circuits in the cruise control ECU to control the operation of the throttle actuator and control/dump valves when the brake pedal has been pressed

Operation of the resume/suspend switch after a braking event can restore the operation of the cruise control system if the vehicles speed and gearbox selector position is acceptable to the cruise control ECU.

Cruise Control Supply

Circuit supply
A feed from the battery positive terminal is connected by a R wire to the engine compartment fusebox, where it passes through fuse 16 and fusible link 8.

A feed from fuse 16 passes to the coil of the horn relay. From the coil of the horn relay, the feed is connected to the set/accel and res/suspend switches on a PO wire, via header C0291 LHD/C0286 RHD and the rotary coupler.

A feed from fusible link 8 is connected to the passenger compartment fusebox on a NW wire and from the fusebox to the ignition switch on a N wire

Ignition switch supply
With the ignition switch in position II, the feed from fusible link 8 flows from the ignition switch to the passenger compartment fusebox on a W wire The feed continues through fuse 30 in the passenger compartment fusebox and is connected by a GLG wire to the cruise control switch.

With the ignition switch in position II, a second feed from fusible link 8 flows from the ignition switch to the passenger compartment fusebox on a Y wire The feed continues through fuse 25 in the passenger compartment fusebox and is connected to the brake pedal switch by a GO wire