Indicators/flashers left hand indicators stay on when selected and dont flash.right side works fine,plus all operate properly when the hazard function is selected.

The smart flasher (GMSF) is an automotive flasher designed to accept turn, hazard, and brake inputs. The GMSF will provide corresponding outputs to the exterior lamps and instrument panel turn signal indicator lamps. This lighting system has dedicated lamps for the turn/hazard functions and dedicated lamps for the brake function. The system incorporates the use of flash rates for diagnostics. The flash rate is a calculation of the number of flashes that occur within a 60 second period. This system uses a percentage of on-time to off-time called duty cycle. For the bulb outage condition, the indicator of the vehicle side on which the outage occurs shall assume bulb outage flash rate mode. The opposite side indicator will assume the normal flash rate mode for an input from the non bulb outage side of the vehicle. Hazard warning lamp outage will maintain a normal flash rate as long as 2 or more exterior signaling lamps are functional. During all modes of operation, the IPC will receive the same flash rates and duty cycles that the exterior lamps receive. The IPC will then control the indicators in the cluster. The vehicle operator will be provided with an audible and visual indication of the flasher operation. Below is a table with flash rates and duty cycles:
Operating Condition
Flash Rate
Duty Cycle
Normal
75 to 105 flashes per minute
45% to 55%
Turn Signal Lamp Outage
2 or 3 times faster than normal flash rate
35% to 55%
The IGN E fuse in the engine wiring harness junction block supplies Ignition positive voltage to the turn signal switch assembly. With the ignition switch in the RUN or START position, ignition positive voltage is connected through the turn signal and hazard switch assembly to the GMSF which is powered by the FLASHER fuse also in the engine wiring harness junction block and is grounded at G201. When the turn signal switch is placed in either the left or right position, the circuit is complete from the GMSF to the turn signal lamps and to ground. The GMSF then sends an on-off voltage signal to either the left or right turn signals and their instrument panel cluster (IPC) indicator. When the hazard switch is pressed, all turn signal lamps will flash including both IPC turn indicators. The front turn signals are grounded at G103 and G107. The rear turn signals are grounded at G401 and G402.
The IPC illuminates the TURN SIGNAL ON indicator in the driver information center when the IPC determines that the turn signal is active for more than 1.2 km (0.75 mile). The IPC also sends a class 2 message to the radio in order to activate the audible warning.
On vehicles equipped with the outside rear view mirror turn signal lamps, the turn signal voltage is also sent to the respective front door module. The door modules then distribute power and ground to the activated lamp.
For trailer wiring, separate turn signal circuits are connected through the GMSF to the trailer wiring harness.

Just left side front and back are not working?

It could need a new turn signal / hazard flasher module.

I would think its a flasher relay or switch problem, do the indicators work when used via the stalk switch ? if they do then I'd start with the hazard switch

Hey Bob how's it going ? I have been looking at Chevy service info for your vehicle and this a little on the complex side or that is the way it sounds from the turn signal description !
Turn Signal Lamps
The smart flasher (GMSF) is an automotive flasher designed to accept turn, hazard, and brake inputs. The GMSF will provide corresponding outputs to the exterior lamps and instrument panel turn signal indicator lamps. This lighting system has dedicated lamps for the turn/hazard functions and dedicated lamps for the brake function. The system incorporates the use of flash rates for diagnostics. The flash rate is a calculation of the number of flashes that occur within a 60 second period. This system uses a percentage of on-time to off-time called duty cycle. For the bulb outage condition, the indicator of the vehicle side on which the outage occurs shall assume bulb outage flash rate mode. The opposite side indicator will assume the normal flash rate mode for an input from the non bulb outage side of the vehicle. Hazard warning lamp outage will maintain a normal flash rate as long as 2 or more exterior signaling lamps are functional. During all modes of operation, the IPC will receive the same flash rates and duty cycles that the exterior lamps receive. The IPC will then control the indicators in the cluster. The vehicle operator will be provided with an audible and visual indication of the flasher operation. Below is a table with flash rates and duty cycles:
Are all your bulbs good ?
Operating Condition
Flash Rate
Duty Cycle
Normal
75 to 105 flashes per minute
45% to 55%
Turn Signal Lamp Outage
2 or 3 times faster than normal flash rate
35% to 55%

try pushing the hazard light switch again. what you have is the hazard lights in operation ( both sides indicators working) In normal indicator operation power from the flasher unit is directed to which ever side you select but by pressing the hazard light switch the indicator power lights up all lights.

flasher relay under steering column does not work,switched it with hazard and see if it works,then get the new one,make sure the light on turn signal in front or back is not burned out first

In my case the left front turn indicator lamp worked, but not the left rear indicator, although all the lamps would turn on with running lights activated, as well as the backup light and 'night-light' mode. The left rear turn indicator would not work with the hazard lights activated. I tested the combination switch (this is the left/right turn indicator switch you use when driving to indicate which direction you are going and is mounted/located on the steering column) and it tested O.K.. I had good continuity from the combination switch black wire, and resistance on the blue-white wire from there to the left rear turn indicator lamp, as well as good continuity on all wires going out from the left parking light fuse. Since the Haynes manual indicated that the flasher module was probably good if it made the tell-tale clicking sound, I was feeling perplexed. So I took it into a local shop that specialized in auto electrics and it turned out to be the flasher module. I was under the impression that it operated in a straight-forward left-right manner, but apparently it has a different circuit for each turn indicator lamp. So even if it is making the appropriate clicking sound when the combo switch is flipped, it could still be the flasher module. Obviously the manual leaves a bit to be desired in the troubleshooting of malfunctioning turn indicators.

If this is not working on the right side and is OK on the left side then one of the indicator lamps on the right side has blown out. The reduced load on the right hand indicators causes the flasher can to flash faster.
Try turning on the hazard switch then walk around your car to see which lamp has blown out.

First, is it doing it on BOTH isdes or just on one side? Example: turn signnals flash OK when turning left, but only come on and stay on when turning right. If it is doing this, then you most likely have either a blown bulb or a bad bulb socket on the side that is not flashing. You need to check both the FRONT and REAR bulbs to make sure they are all functioning properly.
If it is doing it on BOTH sides, then you either have a bad flasher, or at least 2 bulbs burned out (one or more on each side).

Are you sure you replaced the correct flasher? The flasher for the HAZZARD lights is plugged into the convinience center under the left side of the dash. If this is the flasher you replaced, it is the wrong one.
The turn signal flasher is mounted to the driver's knee bolster bar near the steering column. It is held to the bar with a clip. (see diagram)

CHANGE THE BRAKE SENSOR BEHIND THE BRAKE PADEL IT A SWITCH

did you change the battery ? wrong amps or voltage could do that sometimes. it's called reverse polarity.