2000 GMC Jimmy, No Dash lights

This 2000 GMC Jimmy came in with the complaint of no dash lights at night. This is actually pretty easy to test and repair. First turn the park lights on and check to make sure the exterior park/tail lights are working. These were on this vehicle.

Next check for power on the ILLUM fuse in the driver’s side interior fuse box. The panel dimming switch needs to be at full brightness during testing. If it is turned all of the way down the fuse will appear to have no power. Before actually replacing the switch you should check to see if the park lights are working. If they are also not working check the 20 amp PARK LP fuse in the underhood fuse box. If there is power on the ILLUM fuse place the truck in a dark location or use a blanket to cover the dash. Then check all of the bulbs for operation. If there are any illumination bulbs on the problem is not the switch the problem is blown bulbs.

The list of illuminated devices include the instrument cluster, radio, a/c controls, steering wheel controls and  dash mounted switches.

I had to remove one 7 mm headed screw from the trim panel above the instrument cluster. I also had to drop the lower dash trim panel to access two more 7 mm headed screws ath the bottom edges of the main dash panel. I tilted the column all the way down and placed the shifter handle down to D1.

With all of those steps completed  the dash trim panel can now be pulled or unsnapped from the dash. The switches can be unplugged and the panel removed to access the interior screws for the headlight switch assembly.

Sorry, no pictures of actually removing the screws and installing the new switch but,  I did get some pictures of the switch to let you have an idea of how it is mounted.

Further testing of the wiring to the switch should be done before replacing the switch.

Terminal “B”, orange wire should have power at all times. Power is supplied via the PARK LP fuse in the underhood fuse box.

Terminal “K”, dark green wire should have power with the park and/or headlights switched on. The panel dimming switch also needs to be rotated to the full bright position. This wire supplies power to the ILLUM fuse in the driver’s interior fuse box. If power is present when the above conditions are met, the switch is not the problem. If power is not present on the green wire after the above conditions are met, disconnect the harness from the headlight switch. Using a fused jumper wire with a 10 amp fuse , connect the orange wire at terminal “B” to the dark green wire at terminal “K”. The dash lights should now be on at full brightness.

The back side of the switch showing the electrical connection.

Now we have power to the ILLUM fuse in the interior fuse box.

28 discussions on “2000 GMC Jimmy, No Dash lights”

  1. I’m having this issue with my 98 Sonoma. when I test Terminal B and K with a voltmeter it completes a circuit and reads 12 volts. it seems as if terminal k is providing ground. any ideas?

    1. Terminal K is providing a feedback ground through all of the instrument cluster illumination bulbs. Your test, although out of the norm does prove out that the illumination fuse is good and at least some of the bulbs are good. If you were to remove the ILLUM fuse from the interior fuse box you will see that ground disappear.

    2. After removing the illum fuse the ground disappears fromantic terminal K. I’ve since removed the guage cluster then the radio believing them to be the culprit however they were not. What all is connected on this terminal?

      1. You are looking for a problem that is not there. It is normal to have a ground signal flowing through the light bulb elements back to the fuse. A bulb requires a positive and a negative signal for it to work. The ground side is wired in constant and the power is switched through the headlight switch to the ILLUM fuse and then onto the bulbs. What is your actual problem with your Sonoma?

          1. Can I assume that the jumper fuse will not blow if the ILLUM fuse is removed? If it blows with the ILLUM fuse removed the short will be between the headlight switch and the fuse box on the dark green wire. If it only blows with the ILLUM fuse installed the short will be on the gray wires between the ILLUM fuse and multiple components. If the radio is not a factory radio go to the radio wiring and locate the gray wire that is shorted to ground. It could be raw and exposed or someone may have inadvertently connected to to ground. I have seen it a thousand times. If the radio is a factory unit and the wires have not been tampered with there are several other components and their wiring that will need to be checked.

          2. Backprobe the dark green wire at terminal K of the headlight switch connector with the switch plugged in. Turn the switch on and roll the rheostat back and forth. If there is no power on the dark green wire disconnect the headlight switch and jumper terminals K and B together. The dash lights should come on at full brightness. If they do replace the faulty headlight switch assembly.

          3. No dice on the radio. ill start tracing out the gray lines feeding into the blubs on the various locations in the morning. all seem to be wrapped in original factory wiring coverings.

          4. According to the wiring diagrams the gray wire feeds the TBC (Truck Body Control module), instrument cluster, radio, HVAC control head, fog lamp switch, transfer case switch, rear lift gate glass switch, airbag dash module, transmission shifter lever and A/T shift indicator compass trip console. Not all switches or modules may be installed in your truck but keep in mind that many times the base harnesses are the same and the connector may be behind panels where the components would have been installed.

          5. Fixed it, although I’m not sure as to exactly what fixed it. unplugged the BCM from the truck for a few days and replaced the Headlight control switch again. everything seems to be in order.

            Thank you again for all your help.

          6. I vaguely remember there being a metal bracket near the BCM wiring that could cut into a wire. Might just want to make sure wires are secured away from any brackets.

  2. Fuse #9 in the interior fuse box should be for the park lights. Check the wiring behind each of the front park/turn signal light assemblies. Also check the trailer wiring at the rear of the truck.

Share Your Experience: