Left signal lights not working.

[Blake Cardinal]

I just got 02 silverado 2500hd. Im  having a problem with the signal left side signal lights  not working. This is front and back i check the bulbs the running lights works but not the signal lights, i changed the module. And combomation switch because i have a spare truck with the parts i double check them before i swapped them. There no voltage at the lights When signal is on. I check the trailer plug and there is voltage there. I checked fuses.i also check the bcm connector for voltage there is none. I checked the right side and it has voltage. Idk what else to do also doesnt flash quick like if there is a bulb out