Check all fuses related to the dash, and gauges. If non are burned out, you will need to remove the cluster and see if any visible burn or melting has occurred. See if you can have it scanned for codes, if you are lucy something is stored in computer memeory.
INSTRUMENT PANEL -1992 GMC Jimmy
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NOTE: Replace electronic cluster if display is always dim.
DISPLAY BRIGHTNESS CONTROL (ELECTRONIC)
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. See Fig. 1 . On Astro and Safari, check voltage at Brown wire terminal A8 of large instrument cluster connector. See Fig. 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.
Fig. 1: Identifying Electronic Instrument Cluster Connector Terminals
Courtesy of GENERAL MOTORS CORP.
Sunday, September 21st, 2008 AT 1:33 PM