Right turn signals work but left signals don't work

Make sure that all the bulbs are the correct ones and have a good ground.

Why is it you don't take it to the repair shop ? Do you know about automotive electrical circuit's an testing ? Viewing a wiring diagram an using a DVOM - digital volt ohm meter to test . You changed the blub ,but testing the circuit for B+ voltage is what you should have done . Not a fuse problem either . the other's work . Checking for DTC'S - diagnostic trouble code's would be a good first step . The BCM - body control module turns it on an off .

Turn Signal Lamps
The STOP/TURN fuse in the instrument panel (I/P) fuse block supplies battery positive voltage to the body control module (BCM) for the turn signal lamps. When the turn switch is placed in the left or right position, ground is applied to the BCM on the left or right turn signal switch signal circuit. The BCM then applies voltage to the appropriate front and rear supply voltage circuits.
Grounds for the various lamps are as follows:
• G100 supplies the right front lamps
• G101 supplies the left front lamps
• G400 supplies the right rear lamps
• G401 supplies the left rear lamps

DTC B3948 Left Front Turn Signal Circuit
When the turn signal switch is placed in the left turn position, the body control module (BCM) cycles positive voltage ON and OFF to the LF turn signal lamp through the left front turn signal lamp supply voltage circuit. The front turn signal lamps illuminate steady for daytime running lamp (DRL) operation.

Your best bet , take it to a qualified repair shop.

Turn Signal Lamps
The STOP/TURN fuse in the instrument panel (I/P) fuse block supplies battery positive voltage to the body control module (BCM) for the turn signal lamps. When the turn switch is placed in the left or right position, ground is applied to the BCM on the left or right turn signal switch signal circuit. The BCM then applies voltage to the appropriate front and rear supply voltage circuits.
Grounds for the various lamps are as follows:
• G100 supplies the right front lamps
• G101 supplies the left front lamps
• G400 supplies the right rear lamps
• G401 supplies the left rear lamps

Replace the bulb

Bad bulb left rear.

The 2 filament on the LH Front turn signal is most likely burned out, ...........or the ground to it, & the entire socket needs replaced. Caution lights, send signals to ALL FRONT & REAR lights. All turn signal lights must be in working order, as it is a "pulsating" currect surge sent to the bulbs, LH or RH, depending which direction you wisk to turn. If 1 filament is broken, the circuit is incomplete, & no flash will occur. Usually you will get one light that stays on, & the front or rear missing lighting, is the one whichis the culpret.

You have a bad ground wire on the right rear.
if you need further info let me know.

the electronic flasher module may be faulty, or you could have blown a fuse

check the front right bulb