Instrument Panel GMC Jimmy Typhoon

ANALOG INSTRUMENT CLUSTER

Instrument cluster uses analog (needle-type) speedometer and gauges. Indicator light bulbs, plugged into back of cluster, are serviceable, but no other components on cluster are serviceable. If any component on cluster is faulty, replace cluster.

ELECTRONIC INSTRUMENT CLUSTER

Solid-state instrument cluster uses vacuum fluorescent tubes to display vehicle speed and odometer reading in digital form, and gauge readings in bar graph form. Cluster is not serviceable; if faulty, replace cluster.

Odometer display is a separate board attached to main display board. If cluster is replaced, odometer board must be transferred to new cluster to keep vehicle mileage current. Buttons on cluster control the odometer tripmeter. Speedometer and odometer display can be changed from English to metric.

Indicator lights around symbol in bar graph area of each gauge are part of cluster; they cannot be replaced. All other indicator light bulbs are plugged into back of cluster and are serviceable.

ELECTRICAL COMPONENT LOCATIONS

ELECTRICAL COMPONENT LOCATIONS

Coolant Temperature

Gauge responds to resistance of coolant temperature sending unit. As coolant temperature increases, sending unit resistance decreases.

Fuel

Gauge responds to resistance of fuel tank sending unit. As fuel level increases, sending unit resistance increases.

Oil Pressure

Gauge responds to resistance of oil pressure sending unit. As oil pressure increases, sending unit resistance increases.

Tachometer

Gauge (analog) or cluster (electronic) monitors engine RPM through ignition coil signal.

Turbo Boost

Gauge responds to voltage reference of Manifold Absolute Pressure (MAP) sensor circuit. Voltage is proportional to manifold pressure.

Voltmeter

Voltmeter indicates battery voltage (ignition on, engine off) or charging system voltage (engine on).

ANTI-LOCK Or ABS

ANTI-LOCK or ABS light comes on when EHCU detects problem in electrical part of Anti-Lock Brake System (ABS). Light also comes on for 2 seconds after ignition is turned on, and engine is off (EHCU turns on light for 2-second system check). If light stays on after system check, brake system will still operate, but without anti-lock assistance.

If BRAKE light is on, ensure brake hydraulic system is okay before driving vehicle.

BRAKE

When one or more of the following conditions exists, BRAKE light is grounded, turning on light

1. Parking brake switch is closed
2. Brake pressure differential switch is closed (detects loss of hydraulic pressure)
3. EHCU detects problem in hydraulic part of Anti-Lock Brake System (ABS). Light also comes on for 2 seconds after ignition is turned on, and engine is off (EHCU turns on light for 2-second system check).

Charging System (Analog)

One side of battery symbol light bulb is connected to alternator field circuit, and other side to ignition power circuit. When ignition is turned on, bulb is grounded through field circuit. When engine is started, field output equalizes voltage across bulb, turning off light. If charging system output is insufficient, light comes on.

Charging System (Electronic)

Cluster monitors charging system output through alternator field. If output is insufficient or excessive, cluster turns on flashing box around battery symbol in voltmeter bar graph area.

CHECK GAUGES

If coolant temperature exceeds 245°F (118°C) or oil pressure is 10 psi (.7 kg/cm 2 ) or less, light comes on to alert driver of condition indicated by gauges. A CHECK GAUGES light driver (part of coolant temperature gauge) monitors signals from temperature gauge sending unit and oil pressure sending unit. If CHECK GAUGES light driver receives a signal from either sending unit, it grounds the light.

Coolant Temperature (Analog)

See CHECK GAUGES.

Coolant Temperature (Electronic)

Cluster monitors coolant temperature through sending unit. If coolant temperature exceeds 245°F (118°C), cluster turns on flashing box around thermometer symbol in temperature gauge bar graph area.

Low Fuel (Electronic)

Cluster monitors fuel level through fuel tank sending unit. When volume in fuel tank is about 3.0 gals. (11L) or less, cluster turns on flashing box around gas pump symbol in fuel gauge bar graph area.

TURBO COOLANT

Light comes on if coolant level sender is grounded, indicating low coolant level in charge air cooler radiator.

Oil Pressure (Analog)

See CHECK GAUGES.

Oil Pressure (Electronic)

Cluster monitors oil pressure through sending unit. If oil pressure is 10 psi (.7 kg/cm 2 ) or less, cluster turns on flashing box around oil can symbol in oil pressure gauge bar graph area.

SERVICE ENGINE SOON (CHECK ENGINE)

If a problem occurs in engine control system, ECM grounds light. Light should come on when ignition is turned on, then go out when engine starts if no problems exist in engine control system.

Shift (M/T)

Light comes on to tell driver when to upshift for best fuel economy. ECM grounds light. Disregard light during downshift.

SPEEDOMETER & ODOMETER

Vehicle Speed Sensor (VSS) is a permanent magnet, AC signal generator. A toothed rotor (tone wheel) on transmission output shaft rotates near magnetic coil of VSS. VSS generates AC voltage pulses that are sent to a solid-state VSS buffer.

VSS buffer conditions AC voltage pulses and sends them to speedometer. VSS buffer is also known as Digital Ratio Adapter Controller (DRAC) because it is matched to final drive ratio of vehicle. If final drive ratio is changed for any reason (i.e., tire size change or rear axle gear change), VSS buffer must be replaced to maintain accurate speedometer/odometer readings.

Based on AC voltage pulses it receives from VSS buffer, an integrated circuit in the speedometer (analog cluster) or the cluster assembly (electronic cluster) controls the speedometer and odometer. On analog cluster, odometer is driven by a stepper motor.

Note. Incorrect VSS buffer calibration may adversely affect operation of ABS, engine control system and cruise control system.

Analog

Pressing button on cluster resets trip mileage to 0.

Electronic

Pressing TRIP button changes odometer display from total mileage to trip mileage. Pressing RESET button (with display in trip mode) resets trip mileage to 0. Pressing E/M (English/metric) button changes speedometer and odometer display from English (miles) to metric (kilometers).

TESTING

Note. Check GAUGES or IGN/GAU fuse in passenger compartment fuse block before testing. If all components in cluster are inoperative, check instrument cluster power and ground circuits. If power and ground circuits are okay, replace instrument cluster.

Gauge Indicates Cold When Engine Is Hot

Disconnect temperature gauge sending unit connector. Connect jumper between ground and Dark Green wire terminal of sending unit connector. Turn ignition on. If gauge indicates HOT, replace sending unit. If gauge does not indicate HOT, check Dark Green wire between sending unit and cluster. If wire is okay, replace instrument cluster.

Gauge Indicates Hot When Engine Is Cold

Disconnect temperature gauge sending unit connector. Turn ignition on. If gauge indicates COLD, replace sending unit. If gauge still indicates HOT, check Dark Green wire between sending unit and cluster. If wire is okay, replace instrument cluster.

Gauge Is Inaccurate

1. Disconnect temperature gauge sending unit connector. Connect Red wire lead of Instrument Panel Tester (J-33431) to Dark Green wire terminal of sending unit connector, and connect other lead to ground. Turn ignition on.
2. Adjust tester dial to 1400 ohms, then 55 ohms. If gauge indicates COLD with dial at 1400 ohms, and HOT with dial at 55 ohms, replace sending unit. If gauge does not indicate as specified, check Dark Green wire between sending unit and cluster. If wire is okay, replace instrument cluster.

DISPLAY BRIGHTNESS CONTROL (ELECTRONIC)

Note. Replace electronic cluster if display is always dim.

Display Will Not Adjust From Bright To Dim

1. Turn ignition and parking lights on. On all except Astro and Safari, check voltage at Brown wire terminal A6 of instrument cluster connector. (Scheme 1) On Astro and Safari, check voltage at Brown wire terminal A8 of large instrument cluster connector. (Scheme 1)
2. On all vehicles, if battery voltage is not present, repair Brown wire. If battery voltage is present, check voltage at same terminal while rotating panel light dimmer wheel. If voltage varies between zero volts and battery voltage, replace instrument cluster.
3. If voltage does not vary between zero volts and battery voltage, check Gray wire between instrument cluster and fuse; repair as necessary. If wire is okay, replace panel light dimmer.

Scheme 1

Gauge Stays At EMPTY

Disconnect fuel tank sending unit connector. Turn ignition on. If gauge indicates FULL, replace sending unit. If gauge indicates EMPTY, check Purple wire between sending unit and cluster. If wire is okay, replace instrument cluster.

Gauge Stays At FULL

1. Disconnect fuel tank sending unit connector. Turn ignition on. Connect fused jumper wire between ground and Purple wire terminal of sending unit connector. If gauge indicates EMPTY, go to next step. If gauge indicates FULL, check Purple wire between sending unit and cluster. If wire is okay, replace instrument cluster.
2. Connect fused jumper wire between sending unit ground and Purple wire terminal of sending unit connector. If gauge indicates EMPTY, replace sending unit. If gauge still indicates FULL, repair sending unit ground.

1. Disconnect fuel tank sending unit connector. Connect Red lead of Instrument Panel Tester (J-33431) to Purple wire terminal of sending unit connector, and connect other lead to ground. Turn ignition on.
2. Set tester dial to 0 ohms, then 90 ohms. If fuel gauge indicates EMPTY at 0 ohms and FULL at 90 ohms, check sending unit ground. If ground is okay, replace sending unit. If fuel gauge does not indicate as specified, check Purple wire between sending unit and cluster. If wire is okay, replace instrument cluster.

INDICATOR LIGHTS

Note. On electronic cluster, if fuel level, coolant temperature or oil pressure indicator light does not come on during warning condition, replace instrument cluster.

ANTI-LOCK (ABS) Light Does Not Come On During Warning Condition Or Bulb Check

Disconnect EHCU connector. Connect fused jumper wire between ground and White wire terminal of EHCU connector. If light comes on, repair ABS problem. See appropriate ANTI-LOCK BRAKES article in the BRAKES Section. If light does not come on, check for open in White wire between EHCU and instrument cluster. If wire is okay, replace instrument cluster.

BRAKE Light Is On With Parking Brake Off

1. Disconnect parking brake switch connector. If light goes out, adjust parking brake switch. If light stays on, disconnect brake pressure differential switch connector. If light goes out, check for brake hydraulic system leak. If no leaks are found, replace brake pressure differential switch.
2. On vehicles without ABS, if light stays on, check for short to ground in circuit between instrument cluster and parking brake switch, and between instrument cluster and brake pressure differential switch. If wires are okay, replace instrument cluster.
3. On vehicles with ABS, if light stays on, disconnect EHCU connector. If light goes out, repair ABS problem. See appropriate ANTI-LOCK BRAKES article in the BRAKES Section. If light stays on, check for short to ground in each circuit between instrument cluster and the following components: parking brake switch, brake pressure differential switch and EHCU. If circuits are okay, replace instrument cluster.

BRAKE Light Does Not Come On During Warning Condition Or Bulb Check

1. Disconnect parking brake switch connector. Connect fused jumper between parking brake switch connector and ground. If light comes on, adjust parking brake switch. If light does not come on, disconnect brake pressure differential switch connector.
2. Connect fused jumper wire between ground and Tan/White wire terminal of brake pressure differential switch connector. If light comes on, replace brake pressure differential switch. If light does not come on, disconnect EHCU connector. Connect fused jumper wire between ground and Tan/White wire terminal of EHCU connector.
3. If light comes on, repair ABS system. See appropriate ANTI-LOCK BRAKES article in the BRAKES Section. If light does not come on, check for open in each circuit between instrument cluster and the following components: parking brake switch, brake pressure differential switch and EHCU. If circuits are okay, replace instrument cluster.

CHECK GAUGES Light Inoperative During Warning Condition & Bulb Check

Inspect CHECK GAUGES bulb; replace if faulty. If bulb is okay, check for open in printed circuit between oil pressure gauge and temperature gauge, and between temperature gauge and CHECK GAUGES bulb. If printed circuit is open, replace instrument cluster. If printed circuit is okay, replace temperature gauge.

CHECK GAUGES Light Inoperative With High Coolant Temperature

Inspect CHECK GAUGES bulb; replace if faulty. If bulb is okay, check for open in printed circuit between temperature gauge and CHECK GAUGES bulb. If printed circuit is open, replace instrument cluster. If printed circuit is okay, replace temperature gauge.

CHECK GAUGES Light Inoperative With Low Oil Pressure

Inspect CHECK GAUGES bulb; replace if faulty. If bulb is okay, check for open in printed circuit between oil pressure gauge and temperature gauge, and between temperature gauge and CHECK GAUGES bulb. If printed circuit is open, replace instrument cluster. If printed circuit is okay, replace temperature gauge.

TURBO COOLANT Light On, Coolant Level Okay

Disconnect turbo coolant level sensor. Turn ignition on. If light turns off, replace turbo coolant level sensor. If light stays on, check for short to ground in Dark Green wire. If wire is okay, replace instrument cluster.

TURBO COOLANT Light Inoperative

Disconnect turbo coolant level sensor connector. Connect fused jumper wire from ground to turbo coolant level sensor connector. If light comes on, replace turbo coolant level sensor. If light does not come on, check Dark Green wire between turbo coolant level sensor and instrument cluster. If wire is okay, check indicator light bulb. If bulb is okay, replace instrument cluster.

OIL PRESSURE GAUGE

Note. If procedure specifies replacing oil pressure sending unit, replace with revised sending unit. Some older version sending units may cause gauge to indicate oil pressure higher than actual pressure, or may cause gauge fluctuations. Check with manufacturer for latest part number.

Gauge Indicates High When Pressure Is Okay

Disconnect oil pressure sending unit connector. Connect fused jumper wire between ground and Tan wire terminal of sending unit connector. Turn ignition on. If gauge indicates LOW, replace sending unit. If gauge indicates HIGH, check Tan wire between sending unit and cluster. If wire is okay, replace instrument cluster.

Gauge Indicates Low When Pressure Is Okay

Disconnect oil pressure sending unit connector. Turn ignition on. If gauge indicates HIGH, replace sending unit. If gauge indicates LOW, check Tan wire between sending unit and cluster. If wire is okay, replace instrument cluster.

1. Disconnect oil pressure sending unit connector. Connect Red wire lead of Instrument Panel Tester (J-33431) to Tan wire terminal of temperature sending unit connector, and connect other lead to ground. Turn ignition on.
2. Adjust tester dial to 0 ohms, then 90 ohms. If gauge indicates LOW at 0 ohms and HIGH at 90 ohms, replace sending unit. If gauge does not indicate as specified, check Tan wire between sending unit and cluster. If wire is okay, replace instrument cluster.

Note. On electronic cluster, replace cluster if either or both of the following conditions exist

1. Speedometer is inoperative or inaccurate, but odometer is okay.
2. Trip and/or total odometers are inoperative or inaccurate, but speedometer is okay.

Speedometer & Odometer Are Inaccurate

Replace VSS buffer with unit that matches rear axle ratio.

Speedometer & Odometer Do Not Operate

1. Check VSS and VSS buffer. See «VEHICLE SPEED SENSOR & BUFFER»(/gmc/jimmy-typhoon/1992-1993/remont/gauges-instrument-panels/#instrument-panel__vehicle-speed-sensor-buffer) under TESTING. If VSS and VSS buffer are okay, turn ignition off. Disconnect instrument cluster connector and VSS buffer connector.
2. Check resistance of Light Blue/Black wire between instrument cluster connector and VSS buffer connector. If resistance is not about 0 ohms, repair Light Blue/Black wire. If resistance is about 0 ohms, replace instrument cluster.

TRIPMETER

Note. If odometer is inoperative or inaccurate in trip and/or total modes, but speedometer is okay, replace instrument cluster.

Tripmeter Does Not Change From Total To Trip Mileage

1. Disconnect instrument cluster connector. Check continuity between ground and Black wire terminal of tripmeter switch assembly connector. If there is no continuity, repair Black wire.
2. If there is continuity, measure resistance between ground and Light Green wire terminal of instrument cluster connector with TRIP button pressed and released. There should be no resistance with button in one position, and infinite resistance (open) with button in other position.
3. If resistance is as specified, replace instrument cluster. If resistance is not as specified, check Light Green wire between tripmeter switch assembly and instrument cluster connector. If wire is okay, replace tripmeter switch assembly.

Tripmeter Does Not Reset

1. Disconnect instrument cluster connector. Check continuity between ground and Black wire terminal of tripmeter switch assembly connector. If there is no continuity, repair Black wire.
2. If there is continuity, measure resistance between ground and Light Green/Black wire terminal of instrument cluster connector with RESET button pressed and released. There should be no resistance with button in one position, and infinite resistance (open) with button in other position.
3. If resistance is as specified, replace instrument cluster. If resistance is not as specified, check Light Green/Black wire between tripmeter switch assembly and instrument cluster connector. If wire is okay, replace tripmeter switch assembly.

Display Does Not Change From English To Metric

1. Disconnect instrument cluster connector. Check continuity between ground and Black wire terminal of tripmeter switch assembly connector. If there is no continuity, repair Black wire.
2. If there is continuity, measure resistance between ground and Light Blue wire terminal of instrument cluster connector with E/M button pressed and released. There should be no resistance with button in one position, and infinite resistance (open) with button in other position.
3. If resistance is as specified, replace instrument cluster. If resistance is not as specified, check Light Blue wire between tripmeter switch assembly and instrument cluster connector. If wire is okay, replace tripmeter switch assembly.

Turbo Boost Gauge Inoperative

Check for ECM Codes 33 and 34; repair cause of code(s) as necessary. See G - GAS TESTS W/CODES article in the ENGINE PERFORMANCE Section. If no codes are present, check Light Green wire (circuit No. 432) at ECM, or Dark Green wire (circuit No. 932) at instrument cluster. If circuits are okay, replace instrument cluster.

VEHICLE SPEED SENSOR & BUFFER

1. Disconnect VSS buffer connector. Turn ignition on. Check voltage at Pink/White wire terminal of VSS buffer connector. If battery voltage is not present, check Pink/White wire between VSS buffer and fuse.
2. If battery voltage is present, check voltage between Pink/White and Black wire terminals of VSS buffer connector. If battery voltage is not present, repair Black wire between VSS buffer and ground. If battery voltage is present, raise and support vehicle.
3. Check AC voltage between Purple/White and Light Green/Black wire terminals of VSS buffer connector with drive wheels turning in high gear. If pulsing AC voltage is present, go to next step. If pulsing AC voltage is not present, check Purple/White and Light Green/Black wires between VSS buffer and VSS. If wires are okay, replace VSS.
4. Check AC voltage between Light Blue/Black and Black wire terminals of VSS buffer connector with drive wheels turning in high gear. If AC voltage is not present, or if AC voltage is present but does not vary with engine RPM, replace VSS buffer.

Voltmeter Is Inaccurate

Turn ignition on. Check voltage across battery terminals. If battery voltage matches vehicle voltmeter, voltmeter is accurate. If battery voltage does not match vehicle voltmeter, check for resistance in Pink/Black wire between instrument cluster and fuse, and in Black wire between instrument cluster and ground. If wires are okay, replace instrument cluster.

REMOVAL & INSTALLATION

Removal & Installation (Except Astro & Safari)

1. Disconnect negative battery cable. Remove foglight switch (if equipped). Remove headlight switch trim plate. Disconnect headlight switch electrical connector. Remove power mirror adjust switch (if equipped). Remove A/C-heater control assembly. Disconnect A/C-heater control assembly electrical connector.
2. Remove filler panel (lower column trim plate). (Scheme 2) Disconnect shift indicator cable (A/T). Remove instrument cluster housing nuts and cluster. Disconnect cluster electrical connector. To install, reverse removal procedure.

Removal & Installation (Astro & Safari)

Disconnect negative battery cable. Remove lower column trim plate and instrument cluster trim plate. (Scheme 3) Remove instrument cluster. To install, reverse removal procedure.

Scheme 2

Scheme 3

Removal & Installation (Electronic)

Disconnect negative battery terminal. Remove instrument cluster. Disconnect electrical connector from tripmeter switch assembly. Remove tripmeter switch assembly from cluster. To install, reverse removal procedure.

Raise and support vehicle. Disconnect VSS electrical connector. Prepare to catch transmission fluid in a container. Remove VSS. Remove "O" ring. To install, reverse removal procedure. Check transmission fluid level.

Disconnect negative battery cable. Remove trim panel from instrument panel. Disconnect electrical connector from VSS buffer. Remove VSS buffer. To install, reverse removal procedure.

WIRING DIAGRAMS

See appropriate chassis wiring diagram in the WIRING DIAGRAMS Section.

See also:
• VEHICLE SPEED SENSOR & BUFFER