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If vehicle is equipped with air bag, air bag must be deactivated before servicing cruise control components on or around steering column. See appropriate AIR BAG RESTRAINT SYSTEM article in ACCESSORIES & EQUIPMENT. NO CRUISE CONTROL WHEN SET BUTTON IS PRESSED & RELEASED Check for: blown fuse, no vacuum at servo and/or defective servo, disconnected speed control cable, brakelight switch out of adjustment, faulty electrical circuit, faulty Park/Neutral switch input to PCM, faulty PCM. CRUISE CONTROL ENGAGES WITHOUT ACTUATING CRUISE SET BUTTON Check for: defective servo, faulty electrical circuit or control switch. CRUISE CONTROL ENGAGES WHEN ENGINE IS STARTED Check for: defective servo, faulty electrical circuit. ERRATIC SPEED OR ENGINE SHUTS OFF Check for: poor engine performance (surge), defective vehicle speed sensor, vacuum leak, faulty servo, faulty
CRUISE CONTROL DISENGAGES ON ROUGH ROAD Check for: brakelight switch out of adjustment, faulty cruise control switch, faulty electrical circuit. ENGINE DOES NOT RETURN TO NORMAL IDLE Check for: kinked and/or damaged cruise control cable, faulty throttle linkage.

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DESCRIPTION Cruise control system components include cruise control module (control module and electric stepper motor servo combined), cruise control switch, vehicle speed sensor, and brake and clutch release switches. A vehicle speed sensor buffer is used on 1991 Motorhome and 1992 vehicles. CRUISE CONTROL MODULE Cruise control module is mounted on upper radiator support, to left of radiator (Motorhome), or next to master cylinder (all others). See Fig. 1 . Module incorporates an electronic control module and an electric stepper motor servo. Servo regulates throttle position in response to control module commands. Module is not serviceable.

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Heater blower speed resistor Inertia fuel shut off switch Inertia fuel shut off switch – Diesel Interior lamp delay relay Outside air temperature sensor Seat adjustment relay, driver’s side Seat adjustment relay, passenger’s side Steering position sensor Sunroof motor Suspension adjustment valve block, rear Suspension control module Suspension G-force sensor Suspension ride height sensor, front Suspension ride height sensor, rear Vehicle speed sensor Air conditioning air temperature control module (-1994MY) Air conditioning condenser blower motor control module Air conditioning control module Air conditioning control module (1995MY-) Air conditioning refrigerant pressure switch Airbag control module (in steering wheel) Alarm system control module Central locking control module Central locking signal control module Coded keypad Compact disc interface Cruise control actuator valve Cruise control module Cruise control vacuum pump Diagnostic link Door mirror adjustment control module Electric windows control module, right front Engine control module relay 1 Engine control module relay 2 Engine coolant blower motor relay 1

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During “adaptation” with ignition switched on and the engine not running, the Motronic ECM “learns” the closed throttle position (CTP), wide open throttle (WOT) and other positions of the throttle valve control module, and a characteristic curve of the relationship between Throttle Position (TP) sensor -G69- and angle sensor for throttle drive -G187-. Adaptation must be performed if: – The voltage supply is interrupted – The throttle valve control module is removed and installed – The throttle valve control module is replaced – If when installing another engine another throttle valve control module is installed Special tools and equipment VAG1551 or VAG1552 Scan Tool (ST) with VAG1551/3 adapter cable Test conditions – No malfunctions stored in DTC memory. – Battery voltage: min. 11.5 volts – All electrical consumers switched off (radiator coolant fan must not run during test) – A/C switched off – Throttle valve in closed throttle position; if necessary adjust accelerator pedal cable – Cruise control adjustment OK Work sequence – Connect VAG1551 or VAG1552 scan tool and press buttons -0- and -1- to insert “Engine Electronics” address word 01 (with ignition switched on; engine not running). Indicated on display

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The fuse box is located under the dashboard to the left of the steering column. The underhood fuse panel (if equipped) is located beside the battery. The circuits protected by each fuse are listed on the plastic sheet inside the cover. FUSE PANEL IDENTIFICATION (1986-89) 1 – 15 Amp Charge Warning Light, Voltage Regulator, Cooling Fan Timer Control Unit, Fuel Cut-off Relay, Speed Sensor, PGM-FI Main Relay, Fuel Pump, Control Solenoid Valves, Emission Control Unit, Speed Sensor (Automatic Seat Belts, 1988-89) ? 2 – 10 Amp Safety Indicator, Shift Lever Position Indicator, Clock & Gauges, Tachometer, Back-Up Lights, Turn Signal Relay & Lights, Integrated Control Unit, Warning Lights, Cruise Control Indicator, Light Dimming Circuit, Automatic Seat Belt Control Unit, Shift Lock Solenoid (1989) 3 – 20 Amp Wiper Motors, Washer Motors, Intermittent Wiper Relay, Sun Roof Relays,Power Window Relay 4 – 7.5 Amp Cruise Control Unit, Cruise Control Indicator Light 5 – 10 Amp Rear Window Defogger Relay, Rear Window Defogger Indicator Light, Heater Control Amplifier, Fan Motor, A/C Compressor Clutch & Relay, A/C Delay Unit, Heater Control Panel 6 – 10 Amp Right Headlight Low Beam 7 – 10 Amp Left Headlight Low Beam 8 – 15 Amp Left Headlight High Beam 9 – 15 Amp Right Headlight High Beam, High Beam Indicator Light 10 – 7.5 Amp Brake Warning Bulb Check Circuit, PGM-FI ECU, PGM-FI Main Relay, Emission Control Unit 11 – 15 Amp Headlight Retractor Control Unit (Up) 12 – 15 Amp Power Door Mirrors, EFE Heater Unit, Radiator Fan Relay, Cooling Fan Timer Unit 13 – 10 Amp Power Antenna Motor, Stereo Radio/Cassette Player, Power Amplifier (SEi Model) 14 – 15 Amp Vanity Mirror Light, License Plate Lights, Taillights, Rear Side Marker Lights, Dash Light Brightness Control Unit, Cigarette Lighter Illumination, Ashtray Light, Headlight Retractor Control Unit (Light-On), Dash & Switch Lights 15 – UNDERHOOD FUSE PANEL IDENTIFICATION (1986-89)