My tail lights, reverse lights and all backlights controlled by the dimmer switch don't work along with the automatic headlights feature and I hear the tone for my lights being on every time I open the drivers door when all lights are off. Fuses are good and my brake lights Work. Please help. Jm

1. A blown fuse: If one of the fuses responsible for powering the dash lighting has blown, the backlighting will not work. Check the owner's manual to find the location of the fuse box and replace any blown fuses.
2. A faulty dimmer switch: If the dimmer switch is not functioning properly, it could be causing the backlighting to stop working. Try replacing the dimmer switch to see if that fixes the problem.
3. A damaged wiring harness: If the wiring harness that powers the backlighting has been damaged, the backlighting will not work. You may need to have the wiring harness repaired or replaced by a mechanic.
4. A malfunctioning dashboard control module: If none of the above issues are causing the problem, the dashboard control module could be malfunctioning. This will require the attention of a mechanic.

It's also possible that the issue could be caused by a combination of these factors. If you are unable to fix the problem on your own, it's a good idea to have a mechanic diagnose and repair the issue.

There could be several potential causes for both the tail lights and headlights not working and for the headlights turning on the brights when the vehicle is placed in gear. Some possible causes include:

1. A blown fuse: If a fuse has blown, it can cause the lights to stop working. Check the fuse box and replace any blown fuses.
2. A problem with the wiring: If the wiring has become damaged or has come loose, it could cause issues with the lights.
3. A malfunctioning light switch: The light switch might not be functioning properly, which could cause the lights to not work.
4. A problem with the headlight switch: If the headlight switch is malfunctioning, it could cause the headlights to turn on the brights when the vehicle is placed in gear.
5. A problem with the dimmer switch: If the dimmer switch is not functioning properly, it could cause the headlights to turn on the brights when the vehicle is placed in gear.

It's recommended to have a mechanic diagnose the issue to determine the cause and recommend the necessary repairs.

Question edited for typos and English :>D

Google

year make model fuse box diagram

https://www.google.com/search?q=2001+chevy+tahoe+suburban+fuse+box+diagram

It could also be the switch. Or coincidental failure of both bulbs. Check with a test meter.
..

Dashboard backlight works together with the tail light. Both the headlight and tail light is controlled by relays. Check the engine bay fusebox. Look at the inside of the fusebox cover and you can see the 'location map'of relays and fuses. Theheadlight and tail light relays sits side-by-side. Change both and check for blown hedlight fuses..

Here is how they are suppose to work .
Headlamps
The headlamps may be turned on two different ways. First, when the driver places the headlamp switch in the HEADLAMP position, for normal operation. Second, with the headlamp switch placed in the OFF position, for automatic lamp control (ALC). During ALC, the headlamps will be in day time running lamp (DRL) operation in daylight conditions, or low beam operation in low light conditions. The LH HDLPand RH HDLP fuses, supply battery positive voltage from the underhood junction block to the left and right headlamps. The circuit continues through both low and high beam lamps, then back to the underhood junction block. The low beam and high beam circuits continue to the headlamp switch. The low beam and high beam circuits also provide the body control module (BCM) with both low and high beam inputs. The headlamp switch includes the dimmer switch and the flash-to-pass switch. When the headlamp switch is placed in the HEADLAMP position a path to ground is provided. Ground is provided at G201. Depending on the position of the high/low beam switch, either the low or high beam circuit will now have power and ground.
The LH HDLP fuse in the underhood junction block, supplies battery positive voltage to the automatic lamp control (ALC) headlamp relay coil circuit. The ALC relay switch circuit is connected to the low beam circuit at the headlamp switch. When the headlamp switch is placed in the OFF position, the BCM will automatically turn on the low beams in low light conditions. The BCM energizes the ALC relay, closing the switch contacts and grounding the low beam circuit. Ground is provided at G201. With the headlights in the low beam position, the high beams may be momentarily turned on or flashed with the dimmer switch handle. The flash-to-pass feature is accomplished by pulling the dimmer switch handle toward the driver. The headlights may be switched to high beam with the opposite movement of the dimmer switch lever. When the headlamp dimmer switch handle is pulled toward the driver, the flash-to-pass switch closes grounding the high beam circuit. Ground is provided at G201. Both high beams will remain on until the driver releases the switch handle.
If the driver places the headlight switch in the HEADLAMP position , the headlights will remain on until turned off or the battery runs dead.

Finding a wiring diagram to use along with a DMM - digital multi-meter (voltmeter ) To test the electrical circuits for the headlamps B+ power & ground side of the circuit is the way to find a fix .
Watching a few basic electrical testing video's on youtube may help you .
Basic Electricity for Service Techs Ohm law Current Flow Opens Shorts
How to Use Multimeter to Troubleshoot Common Problems
The Trainer 18 Electrical Testing Tips
Can take years to learn how to trouble shoot automotive electrical systems properly .

This is not necessarily your dimmer switch. Most manufacturers tie the dash lights to the tail lights so that it warns you in a visible way if your tail-lights are not working. It sounds more like you have a power supply problem unless working the dimmer switch actually causes or resolves the problem. Chances are you either have a shorting power wire, or a mostly broken wire that is only making an intermittent connection. If it was constant I'd suggest checking fuses but with an intermittent issue, The only way to really check this is to start tracing wires and testing power along them when it's not working. Wiring diagrams help a lot.

Check your fuses. I had the same problem with a 90 Honda civic. Dash lights went out, tail lights also went out. Replaced 1 fuse and all came back on.

No. Dash lights being out could be a bad headlight switch, since the dash lights are routed through the headlight switch, not the dimmer switch. Park and tail lights also controlled by the headlight switch.

I would look more into the headlight switch. Are you getting power to the sockets?

tail lights work on a different filament than the rest of the lights you mentioned, it is possible both bulbs are burned out for that filament. if not, check the fuses as the tail light circuit in some cars is on a seperate fuse. the remaining possibility could be bad socket contacts.