These are electronic units. If one part of the cluster fails, the entire cluster must be replaced. Conventional speedometer cables are not used; the speedometer is a fully electronic unit. Some inputs are hard-wired, such as the turn indicators, high beam indicator and some of the warning lights. All other inputs to the instrument panel cluster are through a Class 2 Serial Data Communications Link. The primary inputs (speedometer, temperature, fuel and tachometer) are driven by information from the data link to the instrument cluster to the cluster microprocessor and then through the stepper motor driver. Although some conventional light bulbs are still being used, Light Emitting Diodes (LEDs) are being used for a number of warning lamps and indicators.
Depending on the vehicle, other information is displayed. Some vehicles may be equipped with a Driver Information Center (DIC) or Message Center. Displays may include the average fuel economy, the range, the fuel used and the oil life remaining. Warning messages may also appear such as Door Ajar, Trunk Ajar, Low Trac, and others. The information is delivered to the driver through tell-tale lamps or the indicators. The tell-tale lamps and indicators illuminate when either a grounding switch is closed or one of the pertinent modules provides a path to ground for the specific indicator. The Driver Information Display does not perform any self-tests or diagnostics and is used only as a communication device for the driver.
Another variation used on some models is the Heads-Up Display (HUD). The instrument cluster HUD system projects the frequently used driver information near the front of the vehicle as viewed from the driver's seat. The instrument cluster HUD system displays speed, turn indicators, high beam indicator, low fuel indicator, the check gauge indicator and radio information. Vehicle using a HUD system have a HUD specific windshield and a special instrument cluster
Although there are many similarities across the W-Body Product Line, there are differences in vehicle equipment, including the instrument panel display and the panel-mounted controls. Your Owner's Manual is a good reference for information specific to your vehicle, what the symbols, lights and chimes mean and what you should look for on the instrument cluster.
Removal & Installation
- Disconnect the negative battery cable. Disarm the SIR system, as outlined in this section.
Remove the instrument panel cluster trim plate using the following procedure:
- Remove the instrument panel access hole covers from the instrument panel using a small flat-bladed tool.
- Remove the screws from each end of the instrument panel cluster trim plate.
- Remove the screw(s) from the lower edge of the right side of the trim plate.
- Open the instrument panel compartment (glove box) door.
- Pull the right lower trim panel plate from the instrument panel.
- Pull the steering column tilt lever and tilt the steering column to its lowest position.
- Grasp the instrument panel cluster trim plate at the right edge and slowly pull, working to the left to release the retainer clips. Remove the instrument panel cluster trim plate from the vehicle.
- Remove the push-pin retainers from the top of the cluster.
- Rotate the instrument cluster rearward and disengage the locating pins on the bottom of the cluster from the instrument panel. Detach the electrical connectors and remove the instrument cluster from the vehicle.
- Installation is the reverse of the removal process. Use care to make sure all installation clips are properly located. Do not over-tighten any screws or they could force their way through their holes and the panel will not be held properly. Squeaks and rattles may develop later.