My 99 chevy silverado 4x4 doesnt work switch indicator lights dont light up ive changed the switch any ideas

Yeah it can. There are thin copper leads in it that scrape across plates. They can get hot and bend loosing contact.

All of those problems happen with a bad ignition switch so you must have bought a bad one from auto zone or you connected it wrong.Did you change the ignition switch or the key cylinder in the steering column because there is a difference?The ignition switch supplies power to the fuses.

You need to have the dealer scan the control module to see what codes show in memory

Which one of these 4X4's does your vehicle have ?
Transfer Case - NVG 246-NP8 (Two Speed Automatic)
Transfer Case - NVG 261-NP2 (Two Speed Manual)

Your brake an CV joint issue can't an won't cause your 4X4 problem . The 4x4 system has a control module which supply's B+ voltage to the switch . Checking for codes in the 4X4 control module should have been the first step . Your best bet , take it to a qualified repair shop . You don't have the knowledge or test equipment to fix this.
SERVICE indicator (4WD/AWD) Lamp
The SERVICE indicator (4WD/AWD) lamp is an integral part of the cluster and cannot be serviced separately. This lamp is used to inform the driver of the vehicle of malfunctions within the automatic transfer case (ATC) system. The SERVICE indicator (4WD/AWD) lamp is controlled by the transfer case shift control module via CKT 1567.

Transfer Case Shift Control Module
The transfer case shift control module uses the VIN information for calculations that are required for the different calibrations used based on axle ratio, transmission, tire size, and engine. The system does not know which calibration to use without this information.
The direct battery supply line (CKT 1640) provides the power to the module and motor circuitry.
Transfer Case Encoder Motor
The transfer case encoder motor consists of a permanent magnet (PM) DC motor and gear reduction assembly. It is located on the left hand side (drivers side) of the transfer case. When activated it turns the sector shaft of the transfer case (clockwise or counter clockwise) to shift the transfer case. The encoder motor is controlled with a pulse width modulated (PWM) circuit within the transfer case shift control module. This circuit consists of a driver on both the Motor A and Motor B circuits. The encoder motor is bi-directional to allow the motor to shift the transfer case from 2HI or 4HI to NEUTRAL and 4LO positions.
Do you know what DTC'S are ?
DTC B2725 ATC Mode Switch Circuit Malfunction
DTC C0300 Rear Speed Sensor Malfunction
DTC C0305 Front Speed Sensor Malfunction
DTC C0308 Motor A/B Circuit Low
DTC C0309 Motor A/B Circuit High
DTC C0310 Motor A/B Circuit Open
DTC C0315 Motor Ground Circuit Open
DTC C0323 T-Case Lock Circuit Low
DTC C0324 T-Case Lock Circuit High
DTC C0327 Encoder Circuit Malfunction
DTC C0367 Front Axle Control Circuit High
DTC C0374 General System Malfunction
DTC C0376 Front/Rear Shaft Speed Mismatch
DTC C0387 Unable to Perform Shift
DTC C0550 ECU Malfunction
DTC C0611 VIN Information Error

vacuum switch needs to be replaced.

bad switch or out of ajustment

sounds like the punch solinoid in the front diff

Replace the selector switch assembly. Common failures.

I would try to replace the switch. I believe that chevy had a bunch of problems with the 4x4 switch. I had a message on the display the something was defective with the 4 wheel drive, and it just ended up being the darn switch. Hope this helps.