Left turn signal, just buzzes, no lights no flashing, but works o.k. in hazard. since the hazard lights on the left work and flash, could this be anything but the combo switch,$249.oo

Get the left signal to flash fast then walk around the car to see which light isn't flashing then change the bulb or socket if they all appear to be flashing (front and rear) turn on the right turn signal then look into the front and rear lens and count the number of bulbs flashing, now do the same thing on the left. Many times there's more than 1 bulb in each lamp. I hope this helps. Take care.

My friend is a part time mechanic he gets his solutions
from www.reliable-store.com
he gets from their every single detailed info, instructions etc. on all vehicles, and manuals like service, repairs, parts, owner's, operations, maintenance etc.
U can get help from there
there is a girl at chat she can help you

When the ignition switch is in the RUN or the START position, voltage is applied through the TURN/LPS fuse to the normally closed contacts of the hazard switch. A single flasher in the hazard switch performs the following functions:
• The turn signal operation
• The hazard flasher operation
When the turn signal switch is in the LEFT position, voltage is applied to the following components:
• The left turn indicator
• The left front park/turn lamp
• The left rear turn lamp
The lamps immediately turn on and flash as the flasher opens and closes the circuit. If a bulb is in need of replacement, the turn lamps will flash at twice the normal rate.
Without testing i would probably say the flasher is bad .
do the four ways work ?

Do you have a burned out bulb, that will affect the speed of the flash

vehicle?????????

lol sounds like my old truck most likely crossed wires

Stop lamp an hazard lights work ?
The body control module (BCM) is responsible for controlling the turn signals and hazard lamps. When the turn signal switch is placed in either the left turn or right turn position, the BCM receives a signal from the turn signal switch. The BCM 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, the BCM receives a signal from the hazard switch. The BCM then will send an on-off voltage signal to all the turn signal lamps. All the turn signal lamps will flash including both IPC turn signal indicators.

Repair an open, high resistance, or short to ground in the inoperative turn signal supply voltage circuit. Refer to Circuit Testing and Wiring Repairs .
Did you complete the repair?

The rear left turn signal bulb must be replaced immediatly before it melts the light socket, if it has'nt yet. Also please verify that the correct light bulb is being installed. because even though many bulbs look the same they are not identical. Installing the wrong bulb can be the begining of many, many problems in the particular circuit

Are you sure the right side bulbs all flash? You say you replaced all the bulbs? Why would you replace bulbs that were working? Did you have this problem before you replaced the bulbs, or after. The hazard flasher is down under the dash, left side, turn the signals on and follow the clicking noise.The hazard flasher and the turn signal flasher should be near each other, and are interchangeable. If it clicks fast, a bulb or a bad socket is usually the cause. These trucks have a lot of problems with the tail light circuit boards.