Lower gauges on instrument panel dont work - 2004 BMW 3 Series

Instrument gauges need to be supplied by a stable voltage in order to be reasonably accurate and because the vehicle battery voltage fluctuates quite a lot it would be useless to operate gauges.
It is for that reason a voltage stabiliser is used and generally mounted on the printed circuit board of the instrument panel. Assuming the supply to the panel is good and there are no other wiring or connection faults the instrument voltage regulator has probably failed.

In the early days the regulator was an electro-mechanical unit but for many years a semiconductor regulator has been used to stabilise the output voltage. Any voltage lower than the lowest battery voltage will theoretically serve but I find most are either 5 volt or 10 volt.

Certainly it seems you must remove the instruments and apply your trusty voltmeter...

Instrument cluster is probably bad, if you are speaking about the gauges that are located above your steering wheel. If you are taking about the lights that illuminate your gauges it could be a bad switch that dims and brightens.

Check the connection on the back of the instrument panel

You need to have the stepper motors replaced , stepper motors make the gauges work ! How to repair GM Instrument Cluster Speedometer Gauge Stepper

I replaced the instrument panel ($40 used part and 45 minute
repair with the help of youtube)

Wow I hope youre mechanicly inclined, big job the entire dash & carrier have to come out 7-15 hr job if you know what you are doing to much to list hear I would check heater hoses at fire wall first make sure they arnt leaking. I wish you well

try checking your fuses under your dash panel to see if one of them is boken/blown

I had the same problem and noticed when I went on a bumpy road that the gauges started working again. It is a short in the wiring because if you hit on the instrument panel with your hand the gauges will work again.

1. Disconnect and isolate the battery negative cable.
2. Remove Over Steering Column Bezel Replacement.
3. Remove over steering column bezel.
4. Remove left end cover.
5. Remove screw at left end of cluster bezel and headlamp switch.
6. Remove screws holding cluster bezel to instrument panel from each side of steering column.
7. Disconnect clip holding cluster bezel to instrument panel from above right vent louver.
   1. Separate cluster bezel from instrument panel.
   2. Disconnect wire connectors from back of the bezel.
   INSTALLATION
   
   1. Connect wire connectors into back of the bezel.
   2. Place cluster bezel in position on instrument panel. Use care not to place hands on louvers.
   3. Connect clips to hold cluster bezel to instrument panel. Use care not to add pressure on the A/C louvers to seat the cluster bezel clips.
   4. Install screws to hold cluster bezel to instrument panel on each side of steering column.
   5. Install screw at left end of cluster bezel and headlamp switch.
   6. Install left end cover.
   7. Install over steering column bezel.
   8. Install lower steering column cover.
   
   I wouldnt Recomend This Procedure To Anyone juse for Cleaning Purposes Unless Your VIEW OF IT IS "SERIOUSYL IMPARED IF it Moisture Has Accumilated Behind Face of it Then Find Out WHY and Resolve THAT PROBLEM FIRST Onherwise Here you Are. Have A Great DAY !! And Please Dont forget to RATE Me Thank You !
   

The light behind myRemove the cluster bezel from the instrument panel. See Cluster Bezel in this group for the procedures.
Remove the four screws that secure the instrument cluster to the instrument panel Instrument Cluster Remove/Install
Pull the instrument cluster rearward to disengage the two self-docking wire harness connectors
NOTE: The instrument cluster has two self-docking wire harness connectors that will be automatically aligned with, and connected to the instrument panel wire harness when the cluster is installed in the instrument panel.
Remove the instrument cluster from the vehicle.
Reverse the removal procedures to install. Tighten the mounting screws to 2.2 N·m (20 in. lbs.)
when I turn my headlights on. All the other gauges are lit, but not the gas gauge. How do I get in there to replace the bulb and fix this? Or is it a fuse problem? I have a 1998 jeep scout Thanks